## Guide to the Secure Configuration of Oracle Linux 7

> with profile NIST National Checklist Program Security Guide
> This compliance profile reflects the core set of security related configuration settings for deployment of Oracle Linux 7 into U.S. Defense, Intelligence, and Civilian agencies. Development partners and sponsors include the U.S. National Institute of Standards and Technology (NIST), U.S. Department of Defense, the National Security Agency, and Red Hat. This baseline implements configuration requirements from the following sources: - Committee on National Security Systems Instruction No. 1253 (CNSSI 1253) - NIST Controlled Unclassified Information (NIST 800-171) - NIST 800-53 control selections for MODERATE impact systems (NIST 800-53) - U.S. Government Configuration Baseline (USGCB) - NIAP Protection Profile for General Purpose Operating Systems v4.2.1 (OSPP v4.2.1) - DISA Operating System Security Requirements Guide (OS SRG) For any differing configuration requirements, e.g. password lengths, the stricter security setting was chosen. Security Requirement Traceability Guides (RTMs) and sample System Security Configuration Guides are provided via the scap-security-guide-docs package. This profile reflects U.S. Government consensus content and is developed through the OpenSCAP/SCAP Security Guide initiative, championed by the National Security Agency. Except for differences in formatting to accommodate publishing processes, this profile mirrors OpenSCAP/SCAP Security Guide content as minor divergences, such as bugfixes, work through the consensus and release processes.

The SCAP Security Guide Project
https://www.open-scap.org/security-policies/scap-security-guide
This guide presents a catalog of security-relevant configuration settings for Oracle Linux 7. It is a rendering of content structured in the eXtensible Configuration Checklist Description Format (XCCDF) in order to support security automation. The SCAP content is is available in the `scap-security-guide` package which is developed at https://www.open-scap.org/security-policies/scap-security-guide.
Providing system administrators with such guidance informs them how to securely configure systems under their control in a variety of network roles. Policy makers and baseline creators can use this catalog of settings, with its associated references to higher-level security control catalogs, in order to assist them in security baseline creation. This guide is a catalog, not a checklist, and satisfaction of every item is not likely to be possible or sensible in many operational scenarios. However, the XCCDF format enables granular selection and adjustment of settings, and their association with OVAL and OCIL content provides an automated checking capability. Transformations of this document, and its associated automated checking content, are capable of providing baselines that meet a diverse set of policy objectives. Some example XCCDF Profiles, which are selections of items that form checklists and can be used as baselines, are available with this guide. They can be processed, in an automated fashion, with tools that support the Security Content Automation Protocol (SCAP). The DISA STIG, which provides required settings for US Department of Defense systems, is one example of a baseline created from this guidance.
Do not attempt to implement any of the settings in this guide without first testing them in a non-operational environment. The creators of this guidance assume no responsibility whatsoever for its use by other parties, and makes no guarantees, expressed or implied, about its quality, reliability, or any other characteristic.

## Profile Information

Profile Title | NIST National Checklist Program Security Guide
Profile ID | xccdf_org.ssgproject.content_profile_ncp

#### CPE Platforms

- cpe:/o:oracle:linux:7

## Revision History

Current version: 0.1.71

- draft (as of 2023-12-16)

## Table of Contents

1. System Settings
   1. Installing and Maintaining Software
   2. Account and Access Control
   3. System Accounting with auditd
   4. GRUB2 bootloader configuration
   5. Configure Syslog
   6. Network Configuration and Firewalls
   7. File Permissions and Masks
   8. SELinux
2. Services
   1. Base Services
   2. Cron and At Daemons
   3. LDAP
   4. NFS and RPC
   5. Network Time Protocol
   6. Obsolete Services
   7. Network Routing
   8. SSH Server
   9. System Security Services Daemon

## Checklist

Group Guide to the Secure Configuration of Oracle Linux 7 Group contains 104 groups and 382 rules
Group System Settings Group contains 79 groups and 328 rules
[ref] Contains rules that check correct system settings.
Group Installing and Maintaining Software Group contains 16 groups and 49 rules
[ref] The following sections contain information on security-relevant choices during the initial operating system installation process and the setup of software updates.
Group System and Software Integrity Group contains 6 groups and 15 rules

[ref] System and software integrity can be gained by installing antivirus, increasing system encryption strength with FIPS, verifying installed software, enabling SELinux, installing an Intrusion Prevention System, etc. However, installing or enabling integrity checking tools cannot prevent intrusions, but they can detect that an intrusion may have occurred. Requirements for integrity checking may be highly dependent on the environment in which the system will be used. Snapshot-based approaches such as AIDE may induce considerable overhead in the presence of frequent software updates.

Group Software Integrity Checking Group contains 2 groups and 9 rules

[ref] Both the AIDE (Advanced Intrusion Detection Environment) software and the RPM package management system provide mechanisms for verifying the integrity of installed software. AIDE uses snapshots of file metadata (such as hashes) and compares these to current system files in order to detect changes.
The RPM package management system can conduct integrity checks by comparing information in its metadata database with files installed on the system.

Group Verify Integrity with RPM Group contains 2 rules

[ref] The RPM package management system includes the ability to verify the integrity of installed packages by comparing the installed files with information about the files taken from the package metadata stored in the RPM database. Although an attacker could corrupt the RPM database (analogous to attacking the AIDE database as described above), this check can still reveal modification of important files. To list which files on the system differ from what is expected by the RPM database:

    $ rpm -qVa

See the man page for `rpm` to see a complete explanation of each column.

#### Rule Verify File Hashes with RPM [ref]

Without cryptographic integrity protections, system executables and files can be altered by unauthorized users without detection. The RPM package management system can check the hashes of installed software packages, including many that are important to system security. To verify that the cryptographic hash of system files and commands matches vendor values, run the following command to list which files on the system have hashes that differ from what is expected by the RPM database:

    $ rpm -Va --noconfig | grep '^..5'

A "c" in the second column indicates that a file is a configuration file, which may appropriately be expected to change. If the file was not expected to change, investigate the cause of the change using audit logs or other means. The package can then be reinstalled to restore the file. Run the following command to determine which package owns the file:

    $ rpm -qf FILENAME

The package can be reinstalled from a yum repository using the command:

    $ sudo yum reinstall PACKAGENAME

Alternatively, the package can be reinstalled from trusted media using the command:

    $ sudo rpm -Uvh PACKAGENAME

Rationale: | The hashes of important files like system executables should match the information given by the RPM database. Executables with erroneous hashes could be a sign of nefarious activity on the system.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_rpm_verify_hashes

Identifiers and References

References: 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.3.8, 3.4.1, CCI-000366, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), PR.DS-6, PR.DS-8, PR.IP-1, Req-11.5, 11.5.2, SRG-OS-000480-GPOS-00227, OL07-00-010020, SV-221653r853660_rule

Remediation Shell script ⇲

    # Find which files have incorrect hash (not in /etc, because of the system related config files) and then get files names
    files_with_incorrect_hash="$(rpm -Va --noconfig | grep -E '^..5' | awk '{print $NF}' )"

    # From files names get package names and change newline to space, because rpm writes each package to new line
    packages_to_reinstall="$(rpm -qf $files_with_incorrect_hash | tr '\n' ' ')"

    yum reinstall -y $packages_to_reinstall

Remediation Ansible snippet ⇲

Complexity: | high
Disruption: | medium
Reboot: | false
Strategy: | restrict

    - name: 'Set fact: Package manager reinstall command (dnf)'
      set_fact:
        package_manager_reinstall_cmd: dnf reinstall -y
      when: ansible_distribution == "Fedora"
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

    - name: 'Set fact: Package manager reinstall command (yum)'
      set_fact:
        package_manager_reinstall_cmd: yum reinstall -y
      when: (ansible_distribution == "RedHat" or ansible_distribution == "CentOS" or ansible_distribution
        == "OracleLinux")
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

    - name: 'Set fact: Package manager reinstall command (zypper)'
      set_fact:
        package_manager_reinstall_cmd: zypper in -f -y
      when: ansible_distribution == "SLES"
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

    - name: Read files with incorrect hash
      command: rpm -Va --nodeps --nosize --nomtime --nordev --nocaps --nolinkto --nouser
        --nogroup --nomode --noghost --noconfig
      register: files_with_incorrect_hash
      changed_when: false
      failed_when: files_with_incorrect_hash.rc > 1
      check_mode: false
      when: (package_manager_reinstall_cmd is defined)
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

    - name: Create list of packages
      command: rpm -qf "{{ item }}"
      with_items: '{{ files_with_incorrect_hash.stdout_lines | map(''regex_findall'',
        ''^[.]+[5]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
        | list | unique }}'
      register: list_of_packages
      changed_when: false
      check_mode: false
      when:
      - files_with_incorrect_hash.stdout_lines is defined
      - (files_with_incorrect_hash.stdout_lines | length > 0)
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

    - name: Reinstall packages of files with incorrect hash
      command: '{{ package_manager_reinstall_cmd }} ''{{ item }}'''
      with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
        | unique }}'
      when:
      - files_with_incorrect_hash.stdout_lines is defined
      - (package_manager_reinstall_cmd is defined and (files_with_incorrect_hash.stdout_lines
        | length > 0))
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010020
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_hashes

#### Rule Verify and Correct File Permissions with RPM [ref]

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. Verify that the file permissions of system files and commands match vendor values. Check the file permissions with the following command:

    $ sudo rpm -Va | awk '{ if (substr($0,2,1)=="M") print $NF }'

Output indicates files that do not match vendor defaults. After locating a file with incorrect permissions, run the following command to determine which package owns it:

    $ rpm -qf FILENAME

Next, run the following command to reset its permissions to the correct values:

    $ sudo rpm --setperms PACKAGENAME

Warning: Profiles may require that specific files have stricter file permissions than defined by the vendor. Such files will be reported as a finding and need to be evaluated according to your policy and deployment environment.

Rationale: | Permissions on system binaries and configuration files that are too generous could allow an unauthorized user to gain privileges that they should not have. The permissions set by the vendor should be maintained. Any deviations from this baseline should be investigated.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_rpm_verify_permissions

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, 5.10.4.1, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.8, 3.4.1, CCI-001493, CCI-001494, CCI-001495, CCI-001496, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-003-8 R6, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CM-6(d), CM-6(c), SI-7, SI-7(1), SI-7(6), AU-9(3), CM-6(a), PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, Req-11.5, 11.5.2, SRG-OS-000256-GPOS-00097, SRG-OS-000257-GPOS-00098, SRG-OS-000258-GPOS-00099, SRG-OS-000278-GPOS-00108, OL07-00-010010, SV-221652r880585_rule

Remediation Shell script ⇲

Complexity: | high
Disruption: | medium
Reboot: | false
Strategy: | restrict

    # Declare array to hold set of RPM packages we need to correct permissions for
    declare -A SETPERMS_RPM_DICT

    # Create a list of files on the system having permissions different from what
    # is expected by the RPM database
    readarray -t FILES_WITH_INCORRECT_PERMS < <(rpm -Va --nofiledigest | awk '{ if (substr($0,2,1)=="M") print $NF }')

    for FILE_PATH in "${FILES_WITH_INCORRECT_PERMS[@]}"
    do
            # NOTE: some files maybe controlled by more then one package
            readarray -t RPM_PACKAGES < <(rpm -qf "${FILE_PATH}")
            for RPM_PACKAGE in "${RPM_PACKAGES[@]}"
            do
                    # Use an associative array to store packages as it's keys, not having to care about duplicates.
                    SETPERMS_RPM_DICT["$RPM_PACKAGE"]=1
            done
    done

    # For each of the RPM packages left in the list -- reset its permissions to the
    # correct values
    for RPM_PACKAGE in "${!SETPERMS_RPM_DICT[@]}"
    do
    	rpm --restore "${RPM_PACKAGE}"
    done

Remediation Ansible snippet ⇲

Complexity: | high
Disruption: | medium
Reboot: | false
Strategy: | restrict

    - name: Read list of files with incorrect permissions
      command: rpm -Va --nodeps --nosignature --nofiledigest --nosize --nomtime --nordev
        --nocaps --nolinkto --nouser --nogroup
      register: files_with_incorrect_permissions
      failed_when: files_with_incorrect_permissions.rc > 1
      changed_when: false
      check_mode: false
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010010
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_permissions

    - name: Create list of packages
      command: rpm -qf "{{ item }}"
      with_items: '{{ files_with_incorrect_permissions.stdout_lines | map(''regex_findall'',
        ''^[.]+[M]+.* (\/.*)'', ''\1'') | map(''join'') | select(''match'', ''(\/.*)'')
        | list | unique }}'
      register: list_of_packages
      changed_when: false
      check_mode: false
      when: (files_with_incorrect_permissions.stdout_lines | length > 0)
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010010
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_permissions

    - name: Correct file permissions with RPM
      command: rpm --setperms '{{ item }}'
      with_items: '{{ list_of_packages.results | map(attribute=''stdout_lines'') | list
        | unique }}'
      when: (files_with_incorrect_permissions.stdout_lines | length > 0)
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-010010
      - NIST-800-171-3.3.8
      - NIST-800-171-3.4.1
      - NIST-800-53-AU-9(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(c)
      - NIST-800-53-CM-6(d)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - NIST-800-53-SI-7(6)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - high_complexity
      - high_severity
      - medium_disruption
      - no_reboot_needed
      - restrict_strategy
      - rpm_verify_permissions

Group Verify Integrity with AIDE Group contains 7 rules
[ref] AIDE conducts integrity checks by comparing information about files with previously-gathered information. Ideally, the AIDE database is created immediately after initial system configuration, and then again after any software update. AIDE is highly configurable, with further configuration information located in `/usr/share/doc/aide-VERSION`.

#### Rule Install AIDE [ref]

The `aide` package can be installed with the following command:

    $ sudo yum install aide

Rationale: | The AIDE package must be installed if it is to be available for integrity checking.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_aide_installed

Identifiers and References

References: BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-002696, CCI-002699, CCI-001744, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, 1034, 1288, 1341, 1417, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000445-GPOS-00199, OL07-00-020029, SV-251701r880693_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    package --add=aide

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Ensure aide is installed
      package:
        name: aide
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020029
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_aide_installed

Remediation OSBuild Blueprint snippet ⇲

    [[packages]]
    name = "aide"
    version = "*"

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include install_aide

    class install_aide {
      package { 'aide':
        ensure => 'installed',
      }
    }

#### Rule Build and Test AIDE Database [ref]

Run the following command to generate a new database:

    $ sudo /usr/sbin/aide --init

By default, the database will be written to the file `/var/lib/aide/aide.db.new.gz`. Storing the database, the configuration file `/etc/aide.conf`, and the binary `/usr/sbin/aide` (or hashes of these files), in a secure location (such as on read-only media) provides additional assurance about their integrity. The newly-generated database can be installed as follows:

    $ sudo cp /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

To initiate a manual check, run the following command:

    $ sudo /usr/sbin/aide --check

If this check produces any unexpected output, investigate.

Rationale: | For AIDE to be effective, an initial database of "known-good" information about files must be captured and it should be able to be verified against the installed files.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_aide_build_database

Identifiers and References

References: BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000445-GPOS-00199, OL07-00-020029, SV-251701r880693_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    /usr/sbin/aide --init
    /bin/cp -p /var/lib/aide/aide.db.new.gz /var/lib/aide/aide.db.gz

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Build and Test AIDE Database - Ensure AIDE Is Installed
      ansible.builtin.package:
        name: '{{ item }}'
        state: present
      with_items:
      - aide
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020029
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_build_database
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Build and Test AIDE Database - Build and Test AIDE Database
      ansible.builtin.command: /usr/sbin/aide --init
      changed_when: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020029
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_build_database
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Build and Test AIDE Database - Check Whether the Stock AIDE Database Exists
      ansible.builtin.stat:
        path: /var/lib/aide/aide.db.new.gz
      register: aide_database_stat
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020029
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_build_database
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Build and Test AIDE Database - Stage AIDE Database
      ansible.builtin.copy:
        src: /var/lib/aide/aide.db.new.gz
        dest: /var/lib/aide/aide.db.gz
        backup: true
        remote_src: true
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (aide_database_stat.stat.exists is defined and aide_database_stat.stat.exists)
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020029
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_build_database
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure Periodic Execution of AIDE [ref]

At a minimum, AIDE should be configured to run a weekly scan. To implement a daily execution of AIDE at 4:05am using cron, add the following line to `/etc/crontab`:

    05 4 * * * root /usr/sbin/aide --check

To implement a weekly execution of AIDE at 4:05am using cron, add the following line to `/etc/crontab`:

    05 4 * * 0 root /usr/sbin/aide --check

AIDE can be executed periodically through other means; this is merely one example. The usage of cron's special time codes, such as `@daily` and `@weekly` is acceptable.

Rationale:

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.
Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.
Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_aide_periodic_cron_checking

Identifiers and References

References: BP28(R51), 1, 11, 12, 13, 14, 15, 16, 2, 3, 5, 7, 8, 9, 5.10.1.3, APO01.06, BAI01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS04.07, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.02, DSS06.06, CCI-001744, CCI-002699, CCI-002702, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 6.2, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.4.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.8.2.3, SI-7, SI-7(1), CM-6(a), DE.CM-1, DE.CM-7, PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, PR.IP-3, Req-11.5, 11.5.2, SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201, OL07-00-020030, SV-221708r902773_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    if ! grep -q "/usr/sbin/aide --check" /etc/crontab ; then
        echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
    else
        sed -i '\!^.* --check.*$!d' /etc/crontab
        echo "05 4 * * * root /usr/sbin/aide --check" >> /etc/crontab
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Ensure AIDE is installed
      package:
        name: '{{ item }}'
        state: present
      with_items:
      - aide
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020030
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_periodic_cron_checking
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set cron package name - RedHat
      set_fact:
        cron_pkg_name: cronie
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_os_family == "RedHat" or ansible_os_family == "Suse"
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020030
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_periodic_cron_checking
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set cron package name - Debian
      set_fact:
        cron_pkg_name: cron
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_os_family == "Debian"
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020030
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_periodic_cron_checking
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Install cron
      package:
        name: '{{ cron_pkg_name }}'
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020030
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_periodic_cron_checking
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure Periodic Execution of AIDE
      cron:
        name: run AIDE check
        minute: 5
        hour: 4
        weekday: 0
        user: root
        job: /usr/sbin/aide --check
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.3
      - DISA-STIG-OL07-00-020030
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - PCI-DSS-Req-11.5
      - PCI-DSSv4-11.5.2
      - aide_periodic_cron_checking
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure Notification of Post-AIDE Scan Details [ref]

AIDE should notify appropriate personnel of the details of a scan after the scan has been run. If AIDE has already been configured for periodic execution in `/etc/crontab`, append the following line to the existing AIDE line:

     | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost

Otherwise, add the following line to `/etc/crontab`:

    05 4 * * * root /usr/sbin/aide --check | /bin/mail -s "$(hostname) - AIDE Integrity Check" root@localhost

AIDE can be executed periodically through other means; this is merely one example.

Rationale:

Unauthorized changes to the baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the operating system. Changes to operating system configurations can have unintended side effects, some of which may be relevant to security.
Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the operating system. The operating system's Information Management Officer (IMO)/Information System Security Officer (ISSO) and System Administrators (SAs) must be notified via email and/or monitoring system trap when there is an unauthorized modification of a configuration item.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_aide_scan_notification

Identifiers and References

References: BP28(R51), 1, 11, 12, 13, 15, 16, 2, 3, 5, 7, 8, 9, BAI01.06, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, CCI-001744, CCI-002699, CCI-002702, 4.3.4.3.2, 4.3.4.3.3, SR 6.2, SR 7.6, A.12.1.2, A.12.4.1, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, CM-6(a), CM-3(5), DE.CM-1, DE.CM-7, PR.IP-1, PR.IP-3, SRG-OS-000363-GPOS-00150, SRG-OS-000446-GPOS-00200, SRG-OS-000447-GPOS-00201, OL07-00-020040, SV-221709r902776_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi
    var_aide_scan_notification_email='root@localhost'

    CRONTAB=/etc/crontab
    CRONDIRS='/etc/cron.d /etc/cron.daily /etc/cron.weekly /etc/cron.monthly'

    # NOTE: on some platforms, /etc/crontab may not exist
    if [ -f /etc/crontab ]; then
    	CRONTAB_EXIST=/etc/crontab
    fi

    if [ -f /var/spool/cron/root ]; then
    	VARSPOOL=/var/spool/cron/root
    fi

    if ! grep -qR '^.*/usr/sbin/aide\s*\-\-check.*|.*\/bin\/mail\s*-s\s*".*"\s*.*@.*$' $CRONTAB_EXIST $VARSPOOL $CRONDIRS; then
    	echo "0 5 * * * root /usr/sbin/aide  --check | /bin/mail -s \"\$(hostname) - AIDE Integrity Check\" $var_aide_scan_notification_email" >> $CRONTAB
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_aide_scan_notification_email # promote to variable
      set_fact:
        var_aide_scan_notification_email: !!str root@localhost
      tags:
        - always

    - name: Ensure AIDE is installed
      package:
        name: '{{ item }}'
        state: present
      with_items:
      - aide
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020040
      - NIST-800-53-CM-3(5)
      - NIST-800-53-CM-6(a)
      - aide_scan_notification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure Notification of Post-AIDE Scan Details
      cron:
        name: run AIDE check
        minute: 5
        hour: 4
        weekday: 0
        user: root
        job: /usr/sbin/aide  --check | /bin/mail -s "$(hostname) - AIDE Integrity Check"
          {{ var_aide_scan_notification_email }}
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020040
      - NIST-800-53-CM-3(5)
      - NIST-800-53-CM-6(a)
      - aide_scan_notification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure AIDE to Use FIPS 140-2 for Validating Hashes [ref]

By default, the `sha512` option is added to the `NORMAL` ruleset in AIDE. If using a custom ruleset or the `sha512` option is missing, add `sha512` to the appropriate ruleset. For example, add `sha512` to the following line in `/etc/aide.conf`:

    NORMAL = FIPSR+sha512

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default.
Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale: | File integrity tools use cryptographic hashes for verifying file contents and directories have not been altered. These hashes must be FIPS 140-2 approved cryptographic hashes.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_aide_use_fips_hashes
Identifiers and References | References: 2, 3, APO01.06, BAI03.05, BAI06.01, DSS06.02, 3.13.11, CCI-000366, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4, SI-7, SI-7(1), CM-6(a), PR.DS-6, PR.DS-8, SRG-OS-000480-GPOS-00227, OL07-00-021620, SV-221761r880699_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    aide_conf="/etc/aide.conf"
    forbidden_hashes=(sha1 rmd160 sha256 whirlpool tiger haval gost crc32)

    groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | cut -f1 -d ' ' | tr -d ' ' | sort -u)

    for group in $groups
    do
    	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

    	if ! [[ $config = *sha512* ]]
    	then
    		config=$config"+sha512"
    	fi

    	for hash in "${forbidden_hashes[@]}"
    	do
    		config=$(echo $config | sed "s/$hash//")
    	done

    	config=$(echo $config | sed "s/^\+*//")
    	config=$(echo $config | sed "s/\+\++/+/")
    	config=$(echo $config | sed "s/\+$//")

    	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

#### Rule Configure AIDE to Verify Access Control Lists (ACLs) [ref]

By default, the `acl` option is added to the `FIPSR` ruleset in AIDE. If using a custom ruleset or the `acl` option is missing, add `acl` to the appropriate ruleset. For example, add `acl` to the following line in `/etc/aide.conf`:

    FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds `acl` to all rule sets available in `/etc/aide.conf`

Rationale: | ACLs can provide permissions beyond those permitted through the file mode and must be verified by the file integrity tools.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_aide_verify_acls
Identifiers and References | References: BP28(R51), 2, 3, APO01.06, BAI03.05, BAI06.01, DSS06.02, CCI-000366, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4, SI-7, SI-7(1), CM-6(a), PR.DS-6, PR.DS-8, SRG-OS-000480-GPOS-00227, OL07-00-021600, SV-221759r880695_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    aide_conf="/etc/aide.conf"

    groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)

    for group in $groups
    do
    	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

    	if ! [[ $config = *acl* ]]
    	then
    		if [[ -z $config ]]
    		then
    			config="acl"
    		else
    			config=$config"+acl"
    		fi
    	fi
    	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather list of packages
      package_facts:
        manager: auto
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ''
      tags:
      - DISA-STIG-OL07-00-021600
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_acls
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Get rules groups
      shell: |
        set -o pipefail
        LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '''aide'' in ansible_facts.packages'
      register: find_rules_groups_results
      tags:
      - DISA-STIG-OL07-00-021600
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_acls
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the acl rule is present when aide is installed.
      replace:
        path: /etc/aide.conf
        regexp: (^\s*{{ item }}\s*=\s*)(?!.*acl)([^\s]*)
        replace: \g<1>\g<2>+acl
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '''aide'' in ansible_facts.packages'
      with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
      tags:
      - DISA-STIG-OL07-00-021600
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_acls
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure AIDE to Verify Extended Attributes [ref]

By default, the `xattrs` option is added to the `FIPSR` ruleset in AIDE. If using a custom ruleset or the `xattrs` option is missing, add `xattrs` to the appropriate ruleset. For example, add `xattrs` to the following line in `/etc/aide.conf`:

    FIPSR = p+i+n+u+g+s+m+c+acl+selinux+xattrs+sha256

AIDE rules can be configured in multiple ways; this is merely one example that is already configured by default. The remediation provided with this rule adds `xattrs` to all rule sets available in `/etc/aide.conf`

Rationale: | Extended attributes in file systems are used to contain arbitrary data and file metadata with security implications.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_aide_verify_ext_attributes
Identifiers and References | References: BP28(R51), 2, 3, APO01.06, BAI03.05, BAI06.01, DSS06.02, CCI-000366, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, A.11.2.4, A.12.2.1, A.12.5.1, A.14.1.2, A.14.1.3, A.14.2.4, SI-7, SI-7(1), CM-6(a), PR.DS-6, PR.DS-8, SRG-OS-000480-GPOS-00227, OL07-00-021610, SV-221760r880697_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "aide" ; then
        yum install -y "aide"
    fi

    aide_conf="/etc/aide.conf"

    groups=$(LC_ALL=C grep "^[A-Z][A-Za-z_]*" $aide_conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u)

    for group in $groups
    do
    	config=$(grep "^$group\s*=" $aide_conf | cut -f2 -d '=' | tr -d ' ')

    	if ! [[ $config = *xattrs* ]]
    	then
    		if [[ -z $config ]]
    		then
    			config="xattrs"
    		else
    			config=$config"+xattrs"
    		fi
    	fi
    	sed -i "s/^$group\s*=.*/$group = $config/g" $aide_conf
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather list of packages
      package_facts:
        manager: auto
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ''
      tags:
      - DISA-STIG-OL07-00-021610
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_ext_attributes
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Get rules groups
      shell: |
        set -o pipefail
        LC_ALL=C grep "^[A-Z][A-Za-z_]*" /etc/aide.conf | grep -v "^ALLXTRAHASHES" | cut -f1 -d '=' | tr -d ' ' | sort -u || true
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '''aide'' in ansible_facts.packages'
      register: find_rules_groups_results
      tags:
      - DISA-STIG-OL07-00-021610
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_ext_attributes
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the xattrs rule is present when aide is installed.
      replace:
        path: /etc/aide.conf
        regexp: (^\s*{{ item }}\s*=\s*)(?!.*xattrs)([^\s]*)
        replace: \g<1>\g<2>+xattrs
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '''aide'' in ansible_facts.packages'
      with_items: '{{ find_rules_groups_results.stdout_lines | map(''trim'') | list }}'
      tags:
      - DISA-STIG-OL07-00-021610
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-7
      - NIST-800-53-SI-7(1)
      - aide_verify_ext_attributes
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

Group Federal Information Processing Standard (FIPS) Group contains 2 rules

[ref] The Federal Information Processing Standard (FIPS) is a computer security standard which is developed by the U.S. Government and industry working groups to validate the quality of cryptographic modules. The FIPS standard provides four security levels to ensure adequate coverage of different industries, implementation of cryptographic modules, and organizational sizes and requirements.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on Oracle Linux 7.
See http://csrc.nist.gov/publications/PubsFIPS.html for more information.

#### Rule Install the dracut-fips Package [ref]

To enable FIPS, the system requires that the `dracut-fips` package be installed. The `dracut-fips` package can be installed with the following command:

    $ sudo yum install dracut-fips

Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale: | Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_dracut-fips_installed

Identifiers and References

References: 12, 15, 8, 5.10.1.2, APO13.01, DSS01.04, DSS05.02, DSS05.03, 3.13.11, 3.13.8, CCI-000068, CCI-000803, CCI-002450, 4.3.3.6.6, SR 1.13, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.6.2.1, A.6.2.2, CIP-003-8 R4.2, CIP-007-3 R5.1, SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12, PR.AC-3, PR.PT-4, SRG-OS-000033-GPOS-00014, SRG-OS-000396-GPOS-00176, SRG-OS-000478-GPOS-00223

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    if ! rpm -q --quiet "dracut-fips" ; then
        yum install -y "dracut-fips"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    package --add=dracut-fips

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Ensure dracut-fips is installed
      package:
        name: dracut-fips
        state: present
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.2
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_dracut-fips_installed

Remediation OSBuild Blueprint snippet ⇲

    [[packages]]
    name = "dracut-fips"
    version = "*"

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include install_dracut-fips

    class install_dracut-fips {
      package { 'dracut-fips':
        ensure => 'installed',
      }
    }

#### Rule Enable FIPS Mode in GRUB2 [ref]

To ensure FIPS mode is enabled, install package `dracut-fips`, and rebuild `initramfs` by running the following commands:

    $ sudo yum install dracut-fips
    dracut -f

After the `dracut` command has been run, add the argument `fips=1` to the default GRUB 2 command line for the Linux operating system in `/etc/default/grub`, in the manner below:

    GRUB_CMDLINE_LINUX="crashkernel=auto rd.lvm.lv=VolGroup/LogVol06 rd.lvm.lv=VolGroup/lv_swap rhgb quiet rd.shell=0 fips=1"

Finally, rebuild the `grub.cfg` file by using the

    grub2-mkconfig -o

command as follows:

- On BIOS-based machines, issue the following command as `root`:

      ~]# grub2-mkconfig -o /boot/grub2/grub.cfg

- On UEFI-based machines, issue the following command as `root`:

      ~]# grub2-mkconfig -o /boot/efi/EFI/redhat/grub.cfg

Warning: Running

    dracut -f

will overwrite the existing initramfs file.
Warning: The system needs to be rebooted for these changes to take effect.
Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale: | Use of weak or untested encryption algorithms undermines the purposes of utilizing encryption to protect data. The operating system must implement cryptographic modules adhering to the higher standards approved by the federal government since this provides assurance they have been tested and validated.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_enable_fips_mode

Identifiers and References

References: 12, 15, 8, 5.10.1.2, APO13.01, DSS01.04, DSS05.02, DSS05.03, 3.13.8, 3.13.11, CCI-000068, CCI-000803, CCI-001199, CCI-002450, CCI-002476, 4.3.3.6.6, SR 1.13, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.6.2.1, A.6.2.2, CIP-003-8 R4.2, CIP-007-3 R5.1, SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12, PR.AC-3, PR.PT-4, SRG-OS-000033-GPOS-00014, SRG-OS-000185-GPOS-00079, SRG-OS-000396-GPOS-00176, SRG-OS-000405-GPOS-00184, SRG-OS-000478-GPOS-00223, OL07-00-021350, SV-221758r877398_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && { rpm --quiet -q grub2-common; }; then

    # prelink not installed
    if test -e /etc/sysconfig/prelink -o -e /usr/sbin/prelink; then
        if grep -q ^PRELINKING /etc/sysconfig/prelink
        then
            sed -i 's/^PRELINKING[:blank:]*=[:blank:]*[:alpha:]*/PRELINKING=no/' /etc/sysconfig/prelink
        else
            printf '\n' >> /etc/sysconfig/prelink
            printf '%s\n' '# Set PRELINKING=no per security requirements' 'PRELINKING=no' >> /etc/sysconfig/prelink
        fi

        # Undo previous prelink changes to binaries if prelink is available.
        if test -x /usr/sbin/prelink; then
            /usr/sbin/prelink -ua
        fi
    fi

    if grep -q -m1 -o aes /proc/cpuinfo; then
    	if ! rpm -q --quiet "dracut-fips-aesni" ; then
        yum install -y "dracut-fips-aesni"
    fi
    fi
    if ! rpm -q --quiet "dracut-fips" ; then
        yum install -y "dracut-fips"
    fi

    dracut -f

    # Correct the form of default kernel command line in  grub
    if grep -q '^GRUB_CMDLINE_LINUX=.*fips=.*"'  /etc/default/grub; then
    	# modify the GRUB command-line if a fips= arg already exists
    	sed -i 's/\(^GRUB_CMDLINE_LINUX=".*\)fips=[^[:space:]]*\(.*"\)/\1 fips=1 \2/'  /etc/default/grub
    else
    	# no existing fips=arg is present, append it
    	sed -i 's/\(^GRUB_CMDLINE_LINUX=".*\)"/\1 fips=1"/'  /etc/default/grub
    fi

    # Get the UUID of the device mounted at root (/).
    ROOT_UUID=$(findmnt --noheadings --output uuid --target /)

    # Get the UUID of the device mounted at /boot.
    BOOT_UUID=$(findmnt --noheadings --output uuid --target /boot)

    if [ "${ROOT_UUID}" == "${BOOT_UUID}" ]; then
    	# root UUID same as boot UUID, so do not modify the GRUB command-line or add boot arg to kernel command line
    	# Correct the form of kernel command line for each installed kernel in the bootloader
    	/sbin/grubby --update-kernel=ALL --args="fips=1"
    else
    	# root UUID different from boot UUID, so modify the GRUB command-line and add boot arg to kernel command line
    	if grep -q '^GRUB_CMDLINE_LINUX=".*boot=.*"'  /etc/default/grub; then
    		# modify the GRUB command-line if a boot= arg already exists
    		sed -i 's/\(^GRUB_CMDLINE_LINUX=".*\)boot=[^[:space:]]*\(.*"\)/\1 boot=UUID='"${BOOT_UUID} \2/" /etc/default/grub
    	else
    		# no existing boot=arg is present, append it
    		sed -i 's/\(^GRUB_CMDLINE_LINUX=".*\)"/\1 boot=UUID='${BOOT_UUID}'"/'  /etc/default/grub
    	fi
    	# Correct the form of kernel command line for each installed kernel in the bootloader
    	/sbin/grubby --update-kernel=ALL --args="fips=1 boot=UUID=${BOOT_UUID}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

    package --add=dracut-fips --add=dracut-fips-aesni

Remediation Ansible snippet ⇲

Complexity: | high
Disruption: | medium
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Check prelink binary installed
      stat:
        path: /usr/sbin/prelink
      register: prelink_exists
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Disable prelink
      lineinfile:
        dest: /etc/sysconfig/prelink
        regexp: ^#?PRELINKING
        line: PRELINKING=no
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - prelink_exists.stat.exists
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Revert prelinking binaries
      command: /usr/sbin/prelink -ua
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - prelink_exists.stat.exists
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Check if system supports AES-NI
      command: grep -q -m1 -o aes /proc/cpuinfo
      failed_when: aesni_supported.rc > 1
      register: aesni_supported
      check_mode: false
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Ensure dracut-fips-aesni is installed
      package:
        name: dracut-fips-aesni
        state: present
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - aesni_supported.rc == 0
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Install dracut-fips
      package:
        name: dracut-fips
        state: present
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Rebuild initramfs
      command: dracut -f
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Check fips argument exists
      command: grep 'GRUB_CMDLINE_LINUX.*fips=' /etc/default/grub
      failed_when: false
      register: fipsargcheck
      check_mode: false
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Replace existing fips argument
      replace:
        path: /etc/default/grub
        regexp: fips=.
        replace: fips=1
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - fipsargcheck.rc == 0
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Add fips argument
      replace:
        path: /etc/default/grub
        regexp: (GRUB_CMDLINE_LINUX=.*)"
        replace: \1 fips=1"
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - fipsargcheck.rc != 0
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Get boot device uuid
      command: findmnt --noheadings --output uuid --target /boot
      register: bootuuid
      check_mode: false
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Check boot argument exists
      command: grep 'GRUB_CMDLINE_LINUX.*boot=' /etc/default/grub
      failed_when: false
      register: bootargcheck
      check_mode: false
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Replace existing boot argument
      replace:
        path: /etc/default/grub
        regexp: boot=\w*-\w*-\w*-\w*-\w*
        replace: boot={{ bootuuid.stdout }}
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - bootargcheck.rc == 0
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Add boot argument
      replace:
        path: /etc/default/grub
        regexp: (GRUB_CMDLINE_LINUX=.*)"
        replace: \1 boot=UUID={{ bootuuid.stdout }}"
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      - bootargcheck.rc != 0
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

    - name: Update bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="fips=1 boot=UUID={{ bootuuid.stdout
        }}"
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.10.1.2
      - DISA-STIG-OL07-00-021350
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - grub2_enable_fips_mode
      - high_complexity
      - high_severity
      - medium_disruption
      - reboot_required
      - restrict_strategy

Group Operating System Vendor Support and Certification Group contains 1 rule

[ref] The assurance of a vendor to provide operating system support and maintenance for their product is an important criterion to ensure product stability and security over the life of the product. A certified product that follows the necessary standards and government certification requirements guarantees that known software vulnerabilities will be remediated, and proper guidance for protecting and securing the operating system will be given.

#### Rule The Installed Operating System Is Vendor Supported [ref]

The installed operating system must be maintained by a vendor. Oracle Linux is supported by Oracle Corporation. As the Oracle Linux vendor, Oracle Corporation is responsible for providing security patches. Warning: There is no remediation besides switching to a different operating system.
Rationale: | An operating system is considered "supported" if the vendor continues to provide security patches for the product. With an unsupported release, it will not be possible to resolve any security issue discovered in the system software.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_installed_OS_is_vendor_supported
Identifiers and References | References: 18, 20, 4, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, CM-6(a), MA-6, SA-13(a), ID.RA-1, PR.IP-12, SRG-OS-000480-GPOS-00227, OL07-00-020250, SV-221719r603260_rule

Group Endpoint Protection Software Group contains 2 rules
[ref] Endpoint protection security software that is not provided or supported by Oracle Corporation can be installed to provide complementary or duplicative security capabilities to those provided by the base platform. Add-on software may not be appropriate for some specialized systems.

#### Rule Install Virus Scanning Software [ref]

Virus scanning software can be used to protect a system from penetration from computer viruses and to limit their spread through intermediate systems. The virus scanning software should be configured to perform scans dynamically on accessed files. If this capability is not available, the system must be configured to scan, at a minimum, all altered files on the system on a daily basis. If the system processes inbound SMTP mail, the virus scanner must be configured to scan all received mail.

Rationale: | Virus scanning software can be used to detect if a system has been compromised by computer viruses, as well as to limit their spread to other systems.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_install_antivirus
Identifiers and References | References: 12, 13, 14, 4, 7, 8, APO01.06, APO13.02, BAI02.01, BAI06.01, DSS04.07, DSS05.01, DSS05.02, DSS05.03, DSS06.06, CCI-000366, CCI-001239, CCI-001668, 4.3.4.3.8, 4.4.3.2, SR 3.2, SR 3.3, SR 3.4, SR 4.1, A.12.2.1, A.14.2.8, A.8.2.3, CM-6(a), DE.CM-4, DE.DP-3, PR.DS-1, SRG-OS-000480-GPOS-00227, OL07-00-032000, SV-221837r603260_rule

#### Rule Install Intrusion Detection Software [ref]

The base Oracle Linux 7 platform already includes a sophisticated auditing system that can detect intruder activity, as well as SELinux, which provides host-based intrusion prevention capabilities by confining privileged programs and user sessions which may become compromised.
Warning: In DoD environments, supplemental intrusion detection and antivirus tools, such as the McAfee Host-based Security System, are available to integrate with existing infrastructure. Per DISA guidance, when these supplemental tools interfere with proper functioning of SELinux, SELinux takes precedence. Should further clarification be required, DISA contact information is published publicly at https://public.cyber.mil/stigs/

Rationale: | Host-based intrusion detection tools provide a system-level defense when an intruder gains access to a system or network.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_install_hids

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 7, 8, 9, APO01.06, APO13.01, DSS01.03, DSS01.05, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, CCI-001263, 4.3.3.4, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), DE.CM-1, PR.AC-5, PR.DS-5, PR.PT-4, Req-11.4

#### Rule Disable Prelinking [ref]

The prelinking feature changes binaries in an attempt to decrease their startup time. In order to disable it, change or add the following line inside the file `/etc/sysconfig/prelink`:

    PRELINKING=no

Next, run the following command to return binaries to a normal, non-prelinked state:

    $ sudo /usr/sbin/prelink -ua

Rationale: | Because the prelinking feature changes binaries, it can interfere with the operation of certain software and/or modes such as AIDE, FIPS, etc.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_disable_prelink

Identifiers and References

References: 11, 13, 14, 2, 3, 9, 5.10.1.3, APO01.06, BAI02.01, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS04.07, DSS05.03, DSS06.02, DSS06.06, 3.13.11, CCI-000803, CCI-002450, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 4.1, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.3, CIP-003-8 R4.2, CIP-007-3 R5.1, SC-13, CM-6(a), PR.DS-1, PR.DS-6, PR.DS-8, PR.IP-1, Req-11.5

Remediation Shell script ⇲

    # prelink not installed
    if test -e /etc/sysconfig/prelink -o -e /usr/sbin/prelink; then
        if grep -q ^PRELINKING /etc/sysconfig/prelink
        then
            sed -i 's/^PRELINKING[:blank:]*=[:blank:]*[:alpha:]*/PRELINKING=no/' /etc/sysconfig/prelink
        else
            printf '\n' >> /etc/sysconfig/prelink
            printf '%s\n' '# Set PRELINKING=no per security requirements' 'PRELINKING=no' >> /etc/sysconfig/prelink
        fi

        # Undo previous prelink changes to binaries if prelink is available.
        if test -x /usr/sbin/prelink; then
            /usr/sbin/prelink -ua
        fi
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Does prelink file exist
      stat:
        path: /etc/sysconfig/prelink
      register: prelink_exists
      tags:
      - CJIS-5.10.1.3
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-13
      - PCI-DSS-Req-11.5
      - disable_prelink
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Disable prelinking
      lineinfile:
        path: /etc/sysconfig/prelink
        regexp: ^PRELINKING=
        line: PRELINKING=no
      when: prelink_exists.stat.exists
      tags:
      - CJIS-5.10.1.3
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-13
      - PCI-DSS-Req-11.5
      - disable_prelink
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Disk Partitioning Group contains 1 rule

[ref] To ensure separation and protection of data, there are top-level system directories which should be placed on their own physical partition or logical volume. The installer's default partitioning scheme creates separate logical volumes for `/`, `/boot`, and `swap`.

- If starting with any of the default layouts, check the box to \"Review and modify partitioning.\" This allows for the easy creation of additional logical volumes inside the volume group already created, though it may require making `/`'s logical volume smaller to create space. In general, using logical volumes is preferable to using partitions because they can be more easily adjusted later.
- If creating a custom layout, create the partitions mentioned in the previous paragraph (which the installer will require anyway), as well as separate ones described in the following sections.

If a system has already been installed, and the default partitioning scheme was used, it is possible but nontrivial to modify it to create separate logical volumes for the directories listed above. The Logical Volume Manager (LVM) makes this possible. See the LVM HOWTO at http://tldp.org/HOWTO/LVM-HOWTO/ for more detailed information on LVM.

#### Rule Encrypt Partitions [ref]

Oracle Linux 7 natively supports partition encryption through the Linux Unified Key Setup-on-disk-format (LUKS) technology. The easiest way to encrypt a partition is during installation time.
For manual installations, select the `Encrypt` checkbox during partition creation to encrypt the partition. When this option is selected the system will prompt for a passphrase to use in decrypting the partition. The passphrase will subsequently need to be entered manually every time the system boots.
For automated/unattended installations, it is possible to use Kickstart by adding the `--encrypted` and `--passphrase=` options to the definition of each partition to be encrypted. For example, the following line would encrypt the root partition:

    part / --fstype=ext4 --size=100 --onpart=hda1 --encrypted --passphrase=PASSPHRASE

Any PASSPHRASE is stored in the Kickstart in plaintext, and the Kickstart must then be protected accordingly. Omitting the `--passphrase=` option from the partition definition will cause the installer to pause and interactively ask for the passphrase during installation.
By default, the `Anaconda` installer uses `aes-xts-plain64` cipher with a minimum `512` bit key size which should be compatible with FIPS enabled.
Detailed information on encrypting partitions using LUKS or LUKS ciphers can be found on the Oracle Linux 7 Documentation web site:
https://docs.oracle.com/en/operating-systems/oracle-linux/7/security/security-SecureInstallationandConfiguration.html#ol7-instcsdp-sec .

Rationale: | The risk of a system's physical compromise, particularly mobile systems such as laptops, places its data at risk of compromise. Encrypting this data mitigates the risk of its loss if the system is lost.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_encrypt_partitions

Identifiers and References

References: 13, 14, APO01.06, BAI02.01, BAI06.01, DSS04.07, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.06, 3.13.16, CCI-001199, CCI-002475, CCI-002476, 164.308(a)(1)(ii)(D), 164.308(b)(1), 164.310(d), 164.312(a)(1), 164.312(a)(2)(iii), 164.312(a)(2)(iv), 164.312(b), 164.312(c), 164.314(b)(2)(i), 164.312(d), SR 3.4, SR 4.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R4.2, CIP-007-3 R5.1, CM-6(a), SC-28, SC-28(1), SC-13, AU-9(3), PR.DS-1, PR.DS-5, SRG-OS-000405-GPOS-00184, SRG-OS-000185-GPOS-00079, SRG-OS-000404-GPOS-00183

Group GNOME Desktop Environment Group contains 6 groups and 27 rules

[ref] GNOME is a graphical desktop environment bundled with many Linux distributions that allow users to easily interact with the operating system graphically rather than textually. The GNOME Graphical Display Manager (GDM) provides login, logout, and user switching contexts as well as display server management.
GNOME is developed by the GNOME Project and is considered the default Oracle Linux Graphical environment.
For more information on GNOME and the GNOME Project, see https://www.gnome.org.

Group Configure GNOME Login Screen Group contains 6 rules

[ref] In the default GNOME desktop, the login is displayed after system boot and can display user accounts, allow users to reboot the system, and allow users to login automatically and/or with a guest account. The login screen should be configured to prevent such behavior.
For more information about enforcing preferences in the GNOME3 environment using the DConf configuration system, see http://wiki.gnome.org/dconf and the man page `dconf(1)`.

#### Rule Disable the GNOME3 Login Restart and Shutdown Buttons [ref]

In the default graphical environment, users logging directly into the system are greeted with a login screen that allows any user, known or unknown, the ability the ability to shutdown or restart the system. This functionality should be disabled by setting `disable-restart-buttons` to `true`.
To disable, add or edit `disable-restart-buttons` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    disable-restart-buttons=true

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/disable-restart-buttons

After the settings have been set, run `dconf update`.

Rationale: | A user who is at the console can reboot the system at the login screen. If restart or shutdown buttons are pressed at the login screen, this can create the risk of short-term loss of availability of systems due to reboot.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_restart_shutdown

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.2, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), CM-7(b), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*disable-restart-buttons\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)disable-restart-buttons(\s*=)/#\1disable-restart-buttons\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*disable-restart-buttons\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*disable-restart-buttons\\s*=\\s*.*/disable-restart-buttons=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\disable-restart-buttons=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/disable-restart-buttons$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/disable-restart-buttons$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/disable-restart-buttons$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/disable-restart-buttons" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_restart_shutdown
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Disable the GNOME3 Login Restart and Shutdown Buttons
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: disable-restart-buttons
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_restart_shutdown
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME disablement of Login Restart and Shutdown
        Buttons
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/disable-restart-buttons
        line: /org/gnome/login-screen/disable-restart-buttons
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_restart_shutdown
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_restart_shutdown
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable the GNOME3 Login User List [ref]

In the default graphical environment, users logging directly into the system are greeted with a login screen that displays all known users. This functionality should be disabled by setting `disable-user-list` to `true`.
To disable, add or edit `disable-user-list` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    disable-user-list=true

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/disable-user-list

After the settings have been set, run `dconf update`.

Rationale: | Leaving the user list enabled is a security risk since it allows anyone with physical access to the system to quickly enumerate known user accounts without logging in.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_list
Identifiers and References | References: CM-6(a), AC-23, SRG-OS-000480-GPOS-00227, OL07-00-010063, SV-256976r902765_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*disable-user-list\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)disable-user-list(\s*=)/#\1disable-user-list\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*disable-user-list\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*disable-user-list\\s*=\\s*.*/disable-user-list=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\disable-user-list=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/disable-user-list$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/disable-user-list$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/disable-user-list$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/disable-user-list" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010063
      - NIST-800-53-AC-23
      - NIST-800-53-CM-6(a)
      - dconf_gnome_disable_user_list
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable the GNOME3 Login User List
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: disable-user-list
        value: 'true'
        no_extra_spaces: true
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010063
      - NIST-800-53-AC-23
      - NIST-800-53-CM-6(a)
      - dconf_gnome_disable_user_list
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 disablement of Login User List
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/disable-user-list$
        line: /org/gnome/login-screen/disable-user-list
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010063
      - NIST-800-53-AC-23
      - NIST-800-53-CM-6(a)
      - dconf_gnome_disable_user_list
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010063
      - NIST-800-53-AC-23
      - NIST-800-53-CM-6(a)
      - dconf_gnome_disable_user_list
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Enable the GNOME3 Login Smartcard Authentication [ref]

In the default graphical environment, smart card authentication can be enabled on the login screen by setting `enable-smartcard-authentication` to `true`.
To enable, add or edit `enable-smartcard-authentication` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    enable-smartcard-authentication=true

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/enable-smartcard-authentication

After the settings have been set, run `dconf update`.

Rationale: | Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_enable_smartcard_auth
Identifiers and References | References: CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000771, CCI-000772, CCI-000884, CCI-001948, CCI-001954, IA-2(3), IA-2(4), IA-2(8), IA-2(9), IA-2(11), Req-8.3, SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161, SRG-OS-000377-GPOS-00162, OL07-00-010061, SV-221658r853661_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*enable-smartcard-authentication\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)enable-smartcard-authentication(\s*=)/#\1enable-smartcard-authentication\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*enable-smartcard-authentication\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*enable-smartcard-authentication\\s*=\\s*.*/enable-smartcard-authentication=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\enable-smartcard-authentication=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/enable-smartcard-authentication$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/enable-smartcard-authentication$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/enable-smartcard-authentication$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/enable-smartcard-authentication" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010061
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - PCI-DSS-Req-8.3
      - dconf_gnome_enable_smartcard_auth
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable the GNOME3 Login Smartcard Authentication
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: enable-smartcard-authentication
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010061
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - PCI-DSS-Req-8.3
      - dconf_gnome_enable_smartcard_auth
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 disablement of Smartcard Authentication
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/enable-smartcard-authentication$
        line: /org/gnome/login-screen/enable-smartcard-authentication
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010061
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - PCI-DSS-Req-8.3
      - dconf_gnome_enable_smartcard_auth
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010061
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - PCI-DSS-Req-8.3
      - dconf_gnome_enable_smartcard_auth
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Set the GNOME3 Login Number of Failures [ref]

In the default graphical environment, the GNOME3 login screen and be configured to restart the authentication process after a configured number of attempts. This can be configured by setting `allowed-failures` to `3` or less.
To enable, add or edit `allowed-failures` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    allowed-failures=3

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/allowed-failures

After the settings have been set, run `dconf update`.

Rationale: | Setting the password retry prompts that are permitted on a per-session basis to a low value requires some software, such as SSH, to re-connect. This can slow down and draw additional attention to some types of password-guessing attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_login_retries
Identifiers and References | References: 3.1.8, FMT_MOF_EXT.1

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*allowed-failures\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)allowed-failures(\s*=)/#\1allowed-failures\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "3")"
    if grep -q "^\\s*allowed-failures\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*allowed-failures\\s*=\\s*.*/allowed-failures=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\allowed-failures=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/allowed-failures$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/allowed-failures$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/allowed-failures$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/allowed-failures" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.8
      - dconf_gnome_login_retries
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable the GNOME3 Login Number of Failures
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: allowed-failures
        value: '3'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.8
      - dconf_gnome_login_retries
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Login Number of Failures
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/allowed-failures$
        line: /org/gnome/login-screen/allowed-failures
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.8
      - dconf_gnome_login_retries
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.8
      - dconf_gnome_login_retries
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable GDM Automatic Login [ref]

The GNOME Display Manager (GDM) can allow users to automatically login without user interaction or credentials. User should always be required to authenticate themselves to the system that they are authorized to use. To disable user ability to automatically login to the system, set the `AutomaticLoginEnable` to `false` in the `[daemon]` section in `/etc/gdm/custom.conf`. For example:

    [daemon]
    AutomaticLoginEnable=false

Rationale: | Failure to restrict system access to authenticated users negatively impacts operating system security.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_gnome_gdm_disable_automatic_login
Identifiers and References | References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.1, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), AC-6(1), CM-7(b), PR.IP-1, FIA_UAU.1, 8.3.1, SRG-OS-000480-GPOS-00229, OL07-00-010440, SV-221694r877377_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    if rpm --quiet -q gdm
    then
    	if ! grep -q "^AutomaticLoginEnable=" /etc/gdm/custom.conf
    	then
    		sed -i "/^\[daemon\]/a \
    		AutomaticLoginEnable=False" /etc/gdm/custom.conf
    	else
    		sed -i "s/^AutomaticLoginEnable=.*/AutomaticLoginEnable=False/g" /etc/gdm/custom.conf
    	fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010440
      - NIST-800-171-3.1.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-8.3.1
      - gnome_gdm_disable_automatic_login
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Disable GDM Automatic Login
      ini_file:
        dest: /etc/gdm/custom.conf
        section: daemon
        option: AutomaticLoginEnable
        value: 'false'
        no_extra_spaces: true
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010440
      - NIST-800-171-3.1.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-8.3.1
      - gnome_gdm_disable_automatic_login
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable GDM Guest Login [ref]

The GNOME Display Manager (GDM) can allow users to login without credentials which can be useful for public kiosk scenarios. Allowing users to login without credentials or "guest" account access has inherent security risks and should be disabled. To do disable timed logins or guest account access, set the `TimedLoginEnable` to `false` in the `[daemon]` section in `/etc/gdm/custom.conf`. For example:

    [daemon]
    TimedLoginEnable=false

Rationale: | Failure to restrict system access to authenticated users negatively impacts operating system security.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_gnome_gdm_disable_guest_login
Identifiers and References | References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.1, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-7(a), CM-7(b), CM-6(a), IA-2, PR.IP-1, FIA_UAU.1, 8.3.1, SRG-OS-000480-GPOS-00229, OL07-00-010450, SV-221695r877377_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    if rpm --quiet -q gdm
    then
    	if ! grep -q "^TimedLoginEnable=" /etc/gdm/custom.conf
    	then
    		sed -i "/^\[daemon\]/a \
    		TimedLoginEnable=false" /etc/gdm/custom.conf
    	else
    		sed -i "s/^TimedLoginEnable=.*/TimedLoginEnable=false/g" /etc/gdm/custom.conf
    	fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010450
      - NIST-800-171-3.1.1
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - PCI-DSSv4-8.3.1
      - gnome_gdm_disable_guest_login
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Disable GDM Guest Login
      ini_file:
        dest: /etc/gdm/custom.conf
        section: daemon
        option: TimedLoginEnable
        value: 'false'
        no_extra_spaces: true
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010450
      - NIST-800-171-3.1.1
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - PCI-DSSv4-8.3.1
      - gnome_gdm_disable_guest_login
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

Group GNOME Media Settings Group contains 4 rules
[ref] GNOME media settings that apply to the graphical interface.

#### Rule Disable GNOME3 Automounting [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable automount within GNOME3, add or set `automount` to `false` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/media-handling]
    automount=false

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/media-handling/automount

After the settings have been set, run `dconf update`.

Rationale: | Disabling automatic mounting in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount

Identifiers and References

References: 12, 16, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, 3.1.7, CCI-000366, CCI-000778, CCI-001958, 4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.AC-6, 3.4.2, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, OL07-00-020111, SV-228567r853730_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*automount\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)automount(\s*=)/#\1automount\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
    if grep -q "^\\s*automount\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*automount\\s*=\\s*.*/automount=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\automount=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/automount$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/media-handling/automount$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/media-handling/automount$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/media-handling/automount" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable GNOME3 Automounting - automount
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/media-handling
        option: automount
        value: 'false'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Automounting - automount
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/media-handling/automount$
        line: /org/gnome/desktop/media-handling/automount
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable GNOME3 Automount Opening [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable automount-open within GNOME3, add or set `automount-open` to `false` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/media-handling]
    automount-open=false

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/media-handling/automount-open

After the settings have been set, run `dconf update`.

Rationale: | Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity. Disabling automatic mounting in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_automount_open

Identifiers and References

References: 12, 16, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, 3.1.7, CCI-000366, CCI-000778, CCI-001958, 4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.AC-6, 3.4.2, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, OL07-00-020111, SV-228567r853730_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*automount-open\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)automount-open(\s*=)/#\1automount-open\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
    if grep -q "^\\s*automount-open\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*automount-open\\s*=\\s*.*/automount-open=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\automount-open=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/automount-open$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/media-handling/automount-open$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/media-handling/automount-open$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/media-handling/automount-open" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount_open
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable GNOME3 Automounting - automount-open
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/media-handling
        option: automount-open
        value: 'false'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount_open
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Automounting - automount-open
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/media-handling/automount-open$
        line: /org/gnome/desktop/media-handling/automount-open
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount_open
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-3.4.2
      - dconf_gnome_disable_automount_open
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable GNOME3 Automount running [ref]

The system's default desktop environment, GNOME3, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. To disable autorun-never within GNOME3, add or set `autorun-never` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/media-handling]
    autorun-never=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/media-handling/autorun-never

After the settings have been set, run `dconf update`.

Rationale: | Automatically mounting file systems permits easy introduction of unknown devices, thereby facilitating malicious activity. Disabling automatic mount running in GNOME3 can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_autorun

Identifiers and References

References: 12, 16, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, 3.1.7, CCI-000366, CCI-000778, CCI-001958, 4.3.3.2.2, 4.3.3.5.2, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.13, SR 1.2, SR 1.4, SR 1.5, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.AC-6, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, OL07-00-020111, SV-228567r853730_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/media-handling\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*autorun-never\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)autorun-never(\s*=)/#\1autorun-never\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/media-handling\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/media-handling]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*autorun-never\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*autorun-never\\s*=\\s*.*/autorun-never=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/media-handling\\]|a\\autorun-never=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/media-handling/autorun-never$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/media-handling/autorun-never$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/media-handling/autorun-never$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/media-handling/autorun-never" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_autorun
      - low_complexity
      - low_severity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Disable GNOME3 Automounting - autorun-never
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/media-handling
        option: autorun-never
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_autorun
      - low_complexity
      - low_severity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Automounting - autorun-never
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/media-handling/autorun-never$
        line: /org/gnome/desktop/media-handling/autorun-never
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_autorun
      - low_complexity
      - low_severity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020111
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_autorun
      - low_complexity
      - low_severity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable All GNOME3 Thumbnailers [ref]

The system's default desktop environment, GNOME3, uses a number of different thumbnailer programs to generate thumbnails for any new or modified content in an opened folder. To disable the execution of these thumbnail applications, add or set `disable-all` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/thumbnailers]
    disable-all=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/thumbnailers/disable-all

After the settings have been set, run `dconf update`. This effectively prevents an attacker from gaining access to a system through a flaw in GNOME3's Nautilus thumbnail creators.

Rationale:

An attacker with knowledge of a flaw in a GNOME3 thumbnailer application could craft a malicious file to exploit this flaw. Assuming the attacker could place the malicious file on the local filesystem (via a web upload for example) and assuming a user browses the same location using Nautilus, the malicious file would exploit the thumbnailer with the potential for malicious code execution. It is best to disable these thumbnailer applications unless they are explicitly required.

Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_thumbnailers

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/thumbnailers\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*disable-all\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)disable-all(\s*=)/#\1disable-all\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/thumbnailers\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/thumbnailers]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*disable-all\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*disable-all\\s*=\\s*.*/disable-all=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/thumbnailers\\]|a\\disable-all=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/thumbnailers/disable-all$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/thumbnailers/disable-all$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/thumbnailers/disable-all$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/thumbnailers/disable-all" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_thumbnailers
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_severity
      - unknown_strategy

    - name: Disable All GNOME3 Thumbnailers
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/thumbnailers
        option: disable-all
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_thumbnailers
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_severity
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Thumbnailers
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/thumbnailers/disable-all$
        line: /org/gnome/desktop/thumbnailers/disable-all
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_thumbnailers
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_severity
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_thumbnailers
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_severity
      - unknown_strategy

Group GNOME Network Settings Group contains 2 rules
[ref] GNOME network settings that apply to the graphical interface.

#### Rule Disable WIFI Network Connection Creation in GNOME3 [ref]

`GNOME` allows users to create ad-hoc wireless connections through the `NetworkManager` applet. Wireless connections should be disabled by adding or setting `disable-wifi-create` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/nm-applet]
    disable-wifi-create=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/nm-applet/disable-wifi-create

After the settings have been set, run `dconf update`.

Rationale: | Wireless network connections should not be allowed to be configured by general users on a given system as it could open the system to backdoor attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_create
Identifiers and References | References: 3.1.16

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/nm-applet\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*disable-wifi-create\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)disable-wifi-create(\s*=)/#\1disable-wifi-create\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/nm-applet\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/nm-applet]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*disable-wifi-create\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*disable-wifi-create\\s*=\\s*.*/disable-wifi-create=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/nm-applet\\]|a\\disable-wifi-create=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/nm-applet/disable-wifi-create$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/nm-applet/disable-wifi-create$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/nm-applet/disable-wifi-create$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/nm-applet/disable-wifi-create" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_create
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable WiFi Network Connection Creation in GNOME3
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/nm-applet
        option: disable-wifi-create
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_create
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 disablement of WiFi
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/nm-applet/disable-wifi-create$
        line: /org/gnome/nm-applet/disable-wifi-create
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_create
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_create
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable WIFI Network Notification in GNOME3 [ref]

By default, `GNOME` disables WIFI notification. This should be permanently set so that users do not connect to a wireless network when the system finds one. While useful for mobile devices, this setting should be disabled for all other systems. To configure the system to disable the WIFI notication, add or set `suppress-wireless-networks-available` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/nm-applet]
    suppress-wireless-networks-available=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/nm-applet/suppress-wireless-networks-available

After the settings have been set, run `dconf update`.

Rationale: | Wireless network connections should not be allowed to be configured by general users on a given system as it could open the system to backdoor attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_wifi_notification
Identifiers and References | References: 3.1.16

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/nm-applet\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*suppress-wireless-networks-available\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)suppress-wireless-networks-available(\s*=)/#\1suppress-wireless-networks-available\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/nm-applet\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/nm-applet]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*suppress-wireless-networks-available\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*suppress-wireless-networks-available\\s*=\\s*.*/suppress-wireless-networks-available=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/nm-applet\\]|a\\suppress-wireless-networks-available=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/nm-applet/suppress-wireless-networks-available$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/nm-applet/suppress-wireless-networks-available$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/nm-applet/suppress-wireless-networks-available$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/nm-applet/suppress-wireless-networks-available" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_notification
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable WiFi Network Notification in GNOME3
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/nm-applet
        option: suppress-wireless-networks-available
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_notification
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 disablement of WiFi
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/nm-applet/suppress-wireless-networks-available$
        line: /org/gnome/nm-applet/suppress-wireless-networks-available
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_notification
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - dconf_gnome_disable_wifi_notification
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

Group GNOME Remote Access Settings Group contains 2 rules
[ref] GNOME remote access settings that apply to the graphical interface.

#### Rule Require Credential Prompting for Remote Access in GNOME3 [ref]

By default, `GNOME` does not require credentials when using `Vino` for remote access. To configure the system to require remote credentials, add or set `authentication-methods` to `['vnc']` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/Vino]
    authentication-methods=['vnc']

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/Vino/authentication-methods

After the settings have been set, run `dconf update`.

Rationale: | Username and password prompting is required for remote access. Otherwise, non-authorized and nefarious users can access the system freely.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_credential_prompt
Identifiers and References | References: 3.1.12, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii)

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/Vino\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*authentication-methods\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)authentication-methods(\s*=)/#\1authentication-methods\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/Vino\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/Vino]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "['vnc']")"
    if grep -q "^\\s*authentication-methods\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*authentication-methods\\s*=\\s*.*/authentication-methods=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/Vino\\]|a\\authentication-methods=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/Vino/authentication-methods$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/Vino/authentication-methods$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/Vino/authentication-methods$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/Vino/authentication-methods" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.12
      - dconf_gnome_remote_access_credential_prompt
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Require Credential Prompting for Remote Access in GNOME3
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/Vino
        option: authentication-methods
        value: '[''vnc'']'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - dconf_gnome_remote_access_credential_prompt
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Credential Prompting for Remote Access
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/Vino/authentication-methods$
        line: /org/gnome/Vino/authentication-methods
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - dconf_gnome_remote_access_credential_prompt
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - dconf_gnome_remote_access_credential_prompt
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Require Encryption for Remote Access in GNOME3 [ref]

By default, `GNOME` requires encryption when using `Vino` for remote access. To prevent remote access encryption from being disabled, add or set `require-encryption` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/Vino]
    require-encryption=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/Vino/require-encryption

After the settings have been set, run `dconf update`.

Rationale: | Open X displays allow an attacker to capture keystrokes and to execute commands remotely.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_remote_access_encryption

Identifiers and References

References: 1, 11, 12, 13, 15, 16, 18, 20, 3, 4, 6, 9, BAI03.08, BAI07.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS03.01, 3.1.13, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 7.6, A.12.1.1, A.12.1.2, A.12.1.4, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-6(a), AC-17(a), AC-17(2), DE.AE-1, PR.DS-7, PR.IP-1, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/Vino\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*require-encryption\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)require-encryption(\s*=)/#\1require-encryption\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/Vino\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/Vino]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*require-encryption\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*require-encryption\\s*=\\s*.*/require-encryption=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/Vino\\]|a\\require-encryption=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/Vino/require-encryption$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/Vino/require-encryption$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/Vino/require-encryption$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/Vino/require-encryption" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - dconf_gnome_remote_access_encryption
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Require Encryption for Remote Access in GNOME3
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/Vino
        option: require-encryption
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - dconf_gnome_remote_access_encryption
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME3 Encryption for Remote Access
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/Vino/require-encryption$
        line: /org/gnome/Vino/require-encryption
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - dconf_gnome_remote_access_encryption
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - dconf_gnome_remote_access_encryption
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

Group Configure GNOME Screen Locking Group contains 8 rules

[ref] In the default GNOME3 desktop, the screen can be locked by selecting the user name in the far right corner of the main panel and selecting Lock.
The following sections detail commands to enforce idle activation of the screensaver, screen locking, a blank-screen screensaver, and an idle activation time.
Because users should be trained to lock the screen when they step away from the computer, the automatic locking feature is only meant as a backup.
The root account can be screen-locked; however, the root account should never be used to log into an X Windows environment and should only be used to for direct login via console in emergency circumstances.
For more information about enforcing preferences in the GNOME3 environment using the DConf configuration system, see http://wiki.gnome.org/dconf and the man page `dconf(1)`.

#### Rule Enable GNOME3 Screensaver Idle Activation [ref]

To activate the screensaver in the GNOME3 desktop after a period of inactivity, add or set `idle-activation-enabled` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/screensaver]
    idle-activation-enabled=true

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/screensaver/idle-activation-enabled

After the settings have been set, run `dconf update`.

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the session lock.
Enabling idle activation of the screensaver ensures the screensaver will be activated after the idle delay. Applications requiring continuous, real-time screen display (such as network management products) require the login session does not have administrator rights and the display station is located in a controlled-access area.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_activation_enabled

Identifiers and References

References: 1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-11(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, OL07-00-010100, SV-221664r880618_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*idle-activation-enabled\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)idle-activation-enabled(\s*=)/#\1idle-activation-enabled\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*idle-activation-enabled\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*idle-activation-enabled\\s*=\\s*.*/idle-activation-enabled=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\idle-activation-enabled=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/idle-activation-enabled$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/screensaver/idle-activation-enabled$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/screensaver/idle-activation-enabled$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/screensaver/idle-activation-enabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010100
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_activation_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable GNOME3 Screensaver Idle Activation
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/screensaver
        option: idle-activation-enabled
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010100
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_activation_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME idle-activation-enabled
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/screensaver/idle-activation-enabled$
        line: /org/gnome/desktop/screensaver/idle-activation-enabled
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010100
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_activation_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010100
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_activation_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Set GNOME3 Screensaver Inactivity Timeout [ref]

The idle time-out value for inactivity in the GNOME3 desktop is configured via the `idle-delay` setting must be set under an appropriate configuration file(s) in the `/etc/dconf/db/local.d` directory and locked in `/etc/dconf/db/local.d/locks` directory to prevent user modification.
For example, to configure the system for a 15 minute delay, add the following to `/etc/dconf/db/local.d/00-security-settings`:

    [org/gnome/desktop/session]
    idle-delay=uint32 900

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME3 can be configured to identify when a user's session has idled and take action to initiate a session lock.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_idle_delay

Identifiers and References

References: 1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(a), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, OL07-00-010070, SV-221660r880606_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    inactivity_timeout_value='900'

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/session\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*idle-delay\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)idle-delay(\s*=)/#\1idle-delay\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/session\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/session]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "uint32 ${inactivity_timeout_value}")"
    if grep -q "^\\s*idle-delay\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*idle-delay\\s*=\\s*.*/idle-delay=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/session\\]|a\\idle-delay=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010070
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
    - name: XCCDF Value inactivity_timeout_value # promote to variable
      set_fact:
        inactivity_timeout_value: !!str 900
      tags:
        - always

    - name: Set GNOME3 Screensaver Inactivity Timeout
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/session
        option: idle-delay
        value: uint32 {{ inactivity_timeout_value }}
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010070
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010070
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_idle_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Set GNOME3 Screensaver Lock Delay After Activation Period [ref]

To activate the locking delay of the screensaver in the GNOME3 desktop when the screensaver is activated, add or set `lock-delay` to `uint32 0` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/screensaver]
    lock-delay=uint32 0

After the settings have been set, run `dconf update`.

Rationale: | A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to logout because of the temporary nature of the absense.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_delay

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000056, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(a), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, OL07-00-010110, SV-221666r880624_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    var_screensaver_lock_delay='0'

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*lock-delay\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)lock-delay(\s*=)/#\1lock-delay\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "uint32 ${var_screensaver_lock_delay}")"
    if grep -q "^\\s*lock-delay\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*lock-delay\\s*=\\s*.*/lock-delay=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\lock-delay=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010110
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
    - name: XCCDF Value var_screensaver_lock_delay # promote to variable
      set_fact:
        var_screensaver_lock_delay: !!str 0
      tags:
        - always

    - name: Set GNOME3 Screensaver Lock Delay After Activation Period
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/screensaver
        option: lock-delay
        value: uint32 {{ var_screensaver_lock_delay }}
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010110
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010110
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_delay
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Enable GNOME3 Screensaver Lock After Idle Period [ref]

To activate locking of the screensaver in the GNOME3 desktop when it is activated, add or set `lock-enabled` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/screensaver]
    lock-enabled=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/screensaver/lock-enabled

After the settings have been set, run `dconf update`.

Rationale: | A session lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not want to logout because of the temporary nature of the absense.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_lock_enabled

Identifiers and References

References: 1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000056, CCI-000058, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000028-GPOS-00009, SRG-OS-000030-GPOS-00011, OL07-00-010060, SV-221657r880600_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*lock-enabled\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)lock-enabled(\s*=)/#\1lock-enabled\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*lock-enabled\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*lock-enabled\\s*=\\s*.*/lock-enabled=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\lock-enabled=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/lock-enabled$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/screensaver/lock-enabled$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/screensaver/lock-enabled$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/screensaver/lock-enabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable GNOME3 Screensaver Lock After Idle Period
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/screensaver
        option: lock-enabled
        value: 'true'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution != 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME lock-enabled
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/screensaver/lock-enabled$
        line: /org/gnome/desktop/screensaver/lock-enabled
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution != 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable GNOME3 Screensaver Lock After Idle Period
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/lockdown
        option: disable-lock-screen
        value: 'false'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME disable-lock-screen
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/lockdown/disable-lock-screen$
        line: /org/gnome/desktop/lockdown/disable-lock-screen
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Check GNOME3 screenserver disable-lock-screen false
      command: gsettings get org.gnome.desktop.lockdown disable-lock-screen
      register: cmd_out
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Update GNOME3 screenserver disable-lock-screen false
      command: gsettings set org.gnome.desktop.lockdown disable-lock-screen false
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'SLES'
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - DISA-STIG-OL07-00-010060
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_lock_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Implement Blank Screensaver [ref]

To set the screensaver mode in the GNOME3 desktop to a blank screen, add or set `picture-uri` to `string ''` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/screensaver]
    picture-uri=string ''

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/screensaver/picture-uri

After the settings have been set, run `dconf update`.

Rationale: | Setting the screensaver mode to blank-only conceals the contents of the display from passersby.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_mode_blank

Identifiers and References

References: 1, 12, 15, 16, 5.5.5, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-11(1), CM-6(a), AC-11(1).1, PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000031-GPOS-00012

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*picture-uri\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)picture-uri(\s*=)/#\1picture-uri\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "string ''")"
    if grep -q "^\\s*picture-uri\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*picture-uri\\s*=\\s*.*/picture-uri=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\picture-uri=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/picture-uri$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/screensaver/picture-uri$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/screensaver/picture-uri$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/screensaver/picture-uri" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.5
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(1)
      - NIST-800-53-AC-11(1).1
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_mode_blank
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Implement Blank Screensaver
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/screensaver
        option: picture-uri
        value: string ''
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(1)
      - NIST-800-53-AC-11(1).1
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_mode_blank
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME picture-uri
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/screensaver/picture-uri$
        line: /org/gnome/desktop/screensaver/picture-uri
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(1)
      - NIST-800-53-AC-11(1).1
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_mode_blank
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.5
      - NIST-800-171-3.1.10
      - NIST-800-53-AC-11(1)
      - NIST-800-53-AC-11(1).1
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_screensaver_mode_blank
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable Full User Name on Splash Shield [ref]

By default when the screen is locked, the splash shield will show the user's full name. This should be disabled to prevent casual observers from seeing who has access to the system. This can be disabled by adding or setting `show-full-name-in-top-bar` to `false` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/screensaver]
    show-full-name-in-top-bar=false

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/screensaver/show-full-name-in-top-bar

After the settings have been set, run `dconf update`.

Rationale: | Setting the splash screen to not reveal the logged in user's name conceals who has access to the system from passersby.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_user_info
Identifiers and References | References: FMT_MOF_EXT.1

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/screensaver\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*show-full-name-in-top-bar\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)show-full-name-in-top-bar(\s*=)/#\1show-full-name-in-top-bar\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/screensaver\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/screensaver]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
    if grep -q "^\\s*show-full-name-in-top-bar\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*show-full-name-in-top-bar\\s*=\\s*.*/show-full-name-in-top-bar=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/screensaver\\]|a\\show-full-name-in-top-bar=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/show-full-name-in-top-bar$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/screensaver/show-full-name-in-top-bar$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/screensaver/show-full-name-in-top-bar$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/screensaver/show-full-name-in-top-bar" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - dconf_gnome_screensaver_user_info
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable Full Username on Splash Screen
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/desktop/screensaver
        option: show-full-name-in-top-bar
        value: 'false'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_screensaver_user_info
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME show-full-name-in-top-bar
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/screensaver/show-full-name-in-top-bar$
        line: /org/gnome/desktop/screensaver/show-full-name-in-top-bar
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_screensaver_user_info
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_screensaver_user_info
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Ensure Users Cannot Change GNOME3 Screensaver Settings [ref]

If not already configured, ensure that users cannot change GNOME3 screensaver lock settings by adding `/org/gnome/desktop/screensaver/lock-delay` to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/screensaver/lock-delay

After the settings have been set, run `dconf update`.

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the session lock. As such, users should not be allowed to change session settings.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_screensaver_user_locks

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, OL07-00-010081, SV-221661r880609_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/screensaver/lock-delay$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/screensaver/lock-delay$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/screensaver/lock-delay$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/screensaver/lock-delay" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010081
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - dconf_gnome_screensaver_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME lock-delay
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/screensaver/lock-delay$
        line: /org/gnome/desktop/screensaver/lock-delay
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010081
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - dconf_gnome_screensaver_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010081
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - dconf_gnome_screensaver_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Ensure Users Cannot Change GNOME3 Session Idle Settings [ref]

If not already configured, ensure that users cannot change GNOME3 session idle settings by adding `/org/gnome/desktop/session/idle-delay` to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/session/idle-delay

After the settings have been set, run `dconf update`.

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operating system session prior to vacating the vicinity, GNOME desktops can be configured to identify when a user's session has idled and take action to initiate the session lock. As such, users should not be allowed to change session settings.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_session_idle_user_locks

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000060, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, Req-8.1.8, 8.2.8, SRG-OS-000029-GPOS-00010, SRG-OS-000031-GPOS-00012, OL07-00-010082, SV-221662r880612_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/session/idle-delay$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/session/idle-delay$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/session/idle-delay$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/session/idle-delay" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010082
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_session_idle_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME Session idle-delay
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/session/idle-delay$
        line: /org/gnome/desktop/session/idle-delay
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010082
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_session_idle_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010082
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - dconf_gnome_session_idle_user_locks
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

Group GNOME System Settings Group contains 3 rules

[ref] GNOME provides configuration and functionality to a graphical desktop environment that changes grahical configurations or allow a user to perform actions that users normally would not be able to do in non-graphical mode such as remote access configuration, power policies, Geo-location, etc. Configuring such settings in GNOME will prevent accidential graphical configuration changes by users from taking place.

#### Rule Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME3 [ref]

By default, `GNOME` will reboot the system if the `Ctrl-Alt-Del` key sequence is pressed.
To configure the system to ignore the `Ctrl-Alt-Del` key sequence from the Graphical User Interface (GUI) instead of rebooting the system, add or set `logout` to `''` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/settings-daemon/plugins/media-keys]
    logout=''

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/settings-daemon/plugins/media-keys/logout

After the settings have been set, run `dconf update`.

Rationale: | A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_ctrlaltdel_reboot

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.2, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), CM-7(b), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-020231, SV-228565r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/settings-daemon/plugins/media-keys\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*logout\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)logout(\s*=)/#\1logout\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/settings-daemon/plugins/media-keys\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/settings-daemon/plugins/media-keys]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "''")"
    if grep -q "^\\s*logout\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*logout\\s*=\\s*.*/logout=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/settings-daemon/plugins/media-keys\\]|a\\logout=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/settings-daemon/plugins/media-keys/logout$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/settings-daemon/plugins/media-keys/logout$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/settings-daemon/plugins/media-keys/logout$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/settings-daemon/plugins/media-keys/logout" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020231
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_ctrlaltdel_reboot
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME3
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/settings-daemon/plugins/media-keys
        option: logout
        value: ''''''
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020231
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_ctrlaltdel_reboot
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME disablement of Ctrl-Alt-Del
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/settings-daemon/plugins/media-keys/logout$
        line: /org/gnome/settings-daemon/plugins/media-keys/logout
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020231
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_ctrlaltdel_reboot
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020231
      - NIST-800-171-3.1.2
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - dconf_gnome_disable_ctrlaltdel_reboot
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable Geolocation in GNOME3 [ref]

`GNOME` allows the clock and applications to track and access location information. This setting should be disabled as applications should not track system location. To configure the system to disable location tracking, add or set `enabled` to `false` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/system/location]
    enabled=false

To configure the clock to disable location tracking, add or set `geolocation` to `false` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/clocks]
    geolocation=false

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/system/location/enabled
    /org/gnome/clocks/geolocation

After the settings have been set, run `dconf update`.

Rationale: | Power settings should not be enabled on systems that are not mobile devices. Enabling power settings on non-mobile devices could have unintended processing consequences on standard systems.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_geolocation
Identifiers and References |

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/system/location\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*enabled\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)enabled(\s*=)/#\1enabled\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/system/location\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/system/location]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
    if grep -q "^\\s*enabled\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*enabled\\s*=\\s*.*/enabled=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/system/location\\]|a\\enabled=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/clocks\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*geolocation\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)geolocation(\s*=)/#\1geolocation\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/clocks\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/clocks]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "false")"
    if grep -q "^\\s*geolocation\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*geolocation\\s*=\\s*.*/geolocation=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/clocks\\]|a\\geolocation=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/system/location/enabled$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/system/location/enabled$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/system/location/enabled$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/system/location/enabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/clocks/geolocation$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/clocks/geolocation$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/clocks/geolocation$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/clocks/geolocation" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable Geolocation in GNOME3 - location tracking
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/system/location
        option: enabled
        value: 'false'
        create: true
        no_extra_spaces: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Disable Geolocation in GNOME3 - clock location tracking
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/clocks
        option: gelocation
        value: 'false'
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME geolocation - location tracking
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/system/location/enabled$
        line: /org/gnome/system/location/enabled
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME geolocation - clock location tracking
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/clocks/geolocation$
        line: /org/gnome/clocks/geolocation
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - dconf_gnome_disable_geolocation
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Disable User Administration in GNOME3 [ref]

By default, `GNOME` will allow all users to have some administratrion capability. This should be disabled so that non-administrative users are not making configuration changes. To configure the system to disable user administration capability in the Graphical User Interface (GUI), add or set `user-administration-disabled` to `true` in `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/desktop/lockdown]
    user-administration-disabled=true

Once the settings have been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/desktop/lockdown/user-administration-disabled

After the settings have been set, run `dconf update`.

Rationale: | Allowing all users to have some administratrive capabilities to the system through the Graphical User Interface (GUI) when they would not have them otherwise could allow unintended configuration changes as well as a nefarious user the capability to make system changes such as adding new accounts, etc.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_disable_user_admin
Identifiers and References | References: 3.1.5, FMT_MOD_EXT.1

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/desktop/lockdown\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*user-administration-disabled\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)user-administration-disabled(\s*=)/#\1user-administration-disabled\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/desktop/lockdown\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/desktop/lockdown]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*user-administration-disabled\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*user-administration-disabled\\s*=\\s*.*/user-administration-disabled=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/desktop/lockdown\\]|a\\user-administration-disabled=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/desktop/lockdown/user-administration-disabled$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/desktop/lockdown/user-administration-disabled$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/desktop/lockdown/user-administration-disabled$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/desktop/lockdown/user-administration-disabled" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Detect if user-administration-disabled can be found on /etc/dconf/db/local.d/
      find:
        path: /etc/dconf/db/local.d/
        contains: ^\s*user-administration-disabled
      register: dconf_gnome_disable_user_admin_config_files
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Configure user-administration-disabled - default file
      ini_file:
        dest: /etc/dconf/db/local.d//00-security-settings
        section: org/gnome/desktop/lockdown
        option: user-administration-disabled
        value: 'true'
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - dconf_gnome_disable_user_admin_config_files is defined and dconf_gnome_disable_user_admin_config_files.matched
        == 0
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Configure user-administration-disabled - existing files
      ini_file:
        dest: '{{ item.path }}'
        section: org/gnome/desktop/lockdown
        option: user-administration-disabled
        value: 'true'
        create: true
      with_items: '{{ dconf_gnome_disable_user_admin_config_files.files }}'
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - dconf_gnome_disable_user_admin_config_files is defined and dconf_gnome_disable_user_admin_config_files.matched
        > 0
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Detect if lock for user-administration-disabled can be found on /etc/dconf/db/local.d/
      find:
        path: /etc/dconf/db/local.d/locks
        contains: ^\s*user-administration-disabled
      register: dconf_gnome_disable_user_admin_lock_files
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification user-administration-disabled - default file
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/desktop/lockdown/user-administration-disabled$
        line: /org/gnome/desktop/lockdown/user-administration-disabled
        create: true
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - dconf_gnome_disable_user_admin_lock_files is defined and dconf_gnome_disable_user_admin_lock_files.matched
        == 0
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification user-administration-disabled - existing files
      lineinfile:
        path: '{{ item.path }}'
        regexp: ^/org/gnome/desktop/lockdown/user-administration-disabled$
        line: /org/gnome/desktop/lockdown/user-administration-disabled
        create: true
      with_items: '{{ dconf_gnome_disable_user_admin_lock_files.files }}'
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - dconf_gnome_disable_user_admin_lock_files is defined and dconf_gnome_disable_user_admin_lock_files.matched
        > 0
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update - user-administration-disabled
      command: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.5
      - dconf_gnome_disable_user_admin
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Make sure that the dconf databases are up-to-date with regards to respective keyfiles [ref]

By default, DConf uses a binary database as a data backend. The system-level database is compiled from keyfiles in the /etc/dconf/db/ directory by the

    dconf update

command. More specifically, content present in the following directories:

    /etc/dconf/db/local.d

    /etc/dconf/db/local.d

Rationale: | Unlike text-based keyfiles, the binary database is impossible to check by OVAL. Therefore, in order to evaluate dconf configuration, both have to be true at the same time - configuration files have to be compliant, and the database needs to be more recent than those keyfiles, which gives confidence that it reflects them.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_db_up_to_date
Identifiers and References | References: 164.308(a)(1)(ii)(B), 164.308(a)(5)(ii)(A), Req-6.2, 8.2.8, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-8.2.8
      - dconf_db_up_to_date
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Run dconf update
      ansible.builtin.command:
        cmd: dconf update
      when:
      - '"gdm" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-8.2.8
      - dconf_db_up_to_date
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Configure GNOME3 DConf User Profile [ref]

By default, DConf provides a standard user profile. This profile contains a list of DConf configuration databases. The user profile and database always take the highest priority. As such the DConf User profile should always exist and be configured correctly.
To make sure that the user profile is configured correctly, the `/etc/dconf/profile/user` should be set as follows:

    user-db:user
    system-db:local
    system-db:site
    system-db:distro

Rationale: | Failure to have a functional DConf profile prevents GNOME3 configuration settings from being enforced for all users and allows various security risks.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_enable_dconf_user_profile
Identifiers and References |

Group Updating Software Group contains 6 rules

[ref] The `yum` command line tool is used to install and update software packages. The system also provides a graphical software update tool in the System menu, in the Administration submenu, called Software Update.
Oracle Linux 7 systems contain an installed software catalog called the RPM database, which records metadata of installed packages. Consistently using `yum` or the graphical Software Update for all software installation allows for insight into the current inventory of installed software on the system.

#### Rule Ensure yum Removes Previous Package Versions [ref]

`yum` should be configured to remove previous software components after new versions have been installed. To configure `yum` to remove the previous software components after updating, set the `clean_requirements_on_remove` to `1` in `/etc/yum.conf`.
Rationale: | Previous versions of software components that are not removed from the information system after updates have been installed may be exploited by some adversaries.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_clean_components_post_updating
Identifiers and References | References: 18, 20, 4, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, 3.4.8, CCI-002617, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(6), CM-11(a), CM-11(b), CM-6(a), ID.RA-1, PR.IP-12, SRG-OS-000437-GPOS-00194, OL07-00-020200, SV-221715r853674_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q yum; then

    if grep --silent ^clean_requirements_on_remove /etc/yum.conf ; then
            sed -i "s/^clean_requirements_on_remove.*/clean_requirements_on_remove=1/g" /etc/yum.conf
    else
            echo -e "\n# Set clean_requirements_on_remove to 1 per security requirements" >> /etc/yum.conf
            echo "clean_requirements_on_remove=1" >> /etc/yum.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020200
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-2(6)
      - clean_components_post_updating
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure yum Removes Previous Package Versions - Ensure YUM Removes Previous
        Package Versions
      ansible.builtin.lineinfile:
        dest: /etc/yum.conf
        regexp: ^#?clean_requirements_on_remove
        line: clean_requirements_on_remove=1
        insertafter: \[main\]
        create: true
      when: '"yum" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-020200
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-2(6)
      - clean_components_post_updating
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure gpgcheck Enabled In Main yum Configuration [ref]

The `gpgcheck` option controls whether RPM packages' signatures are always checked prior to installation. To configure yum to check package signatures before installing them, ensure the following line appears in `/etc/yum.conf` in the `[main]` section:

    gpgcheck=1

Rationale:

Changes to any software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor.
Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.
Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA).

Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_globally_activated

Identifiers and References

References: BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, 6.3.3, SRG-OS-000366-GPOS-00153, OL07-00-020050, SV-221710r877463_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q yum; then

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^gpgcheck")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^gpgcheck\\>" "/etc/yum.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
    else
        if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-020050
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SI-7
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-6.3.3
      - configure_strategy
      - ensure_gpgcheck_globally_activated
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed

    - name: Ensure GPG check is globally activated
      ini_file:
        dest: /etc/yum.conf
        section: main
        option: gpgcheck
        value: 1
        no_extra_spaces: true
        create: false
      when: '"yum" in ansible_facts.packages'
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-020050
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SI-7
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-6.3.3
      - configure_strategy
      - ensure_gpgcheck_globally_activated
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed

#### Rule Ensure gpgcheck Enabled for Local Packages [ref]

`yum` should be configured to verify the signature(s) of local packages prior to installation. To configure `yum` to verify signatures of local packages, set the `localpkg_gpgcheck` to `1` in `/etc/yum.conf`.
Rationale: | Changes to any software components can have significant effects to the overall security of the operating system. This requirement ensures the software has not been tampered and has been provided by a trusted vendor. Accordingly, patches, service packs, device drivers, or operating system components must be signed with a certificate recognized and approved by the organization.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_local_packages

Identifiers and References

References: BP28(R15), 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-11(a), CM-11(b), CM-6(a), CM-5(3), SA-12, SA-12(10), PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, SRG-OS-000366-GPOS-00153, OL07-00-020060, SV-221711r877463_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q yum; then

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^localpkg_gpgcheck")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^localpkg_gpgcheck\\>" "/etc/yum.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^localpkg_gpgcheck\\>.*/$escaped_formatted_output/gi" "/etc/yum.conf"
    else
        if [[ -s "/etc/yum.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/yum.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/yum.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/yum.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020060
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - ensure_gpgcheck_local_packages
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

    - name: Ensure GPG check Enabled for Local Packages (yum)
      block:

      - name: Check stats of yum
        stat:
          path: /etc/yum.conf
        register: pkg

      - name: Check if config file of yum is a symlink
        ansible.builtin.set_fact:
          pkg_config_file_symlink: '{{ pkg.stat.lnk_target if pkg.stat.lnk_target is match("^/.*")
            else "/etc/yum.conf" | dirname ~ "/" ~ pkg.stat.lnk_target }}'
        when: pkg.stat.lnk_target is defined

      - name: Ensure GPG check Enabled for Local Packages (yum)
        ini_file:
          dest: '{{ pkg_config_file_symlink |  default("/etc/yum.conf") }}'
          section: main
          option: localpkg_gpgcheck
          value: 1
          no_extra_spaces: true
          create: true
      when: '"yum" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-020060
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - ensure_gpgcheck_local_packages
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed
      - unknown_strategy

#### Rule Ensure gpgcheck Enabled for All yum Package Repositories [ref]

To ensure signature checking is not disabled for any repos, remove any lines from files in `/etc/yum.repos.d` of the form:

    gpgcheck=0

Rationale:

Verifying the authenticity of the software prior to installation validates the integrity of the patch or upgrade received from a vendor. This ensures the software has not been tampered with and that it has been provided by a trusted vendor. Self-signed certificates are disallowed by this requirement. Certificates used to verify the software must be from an approved Certificate Authority (CA)."

Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_ensure_gpgcheck_never_disabled

Identifiers and References

References: BP28(R15), 11, 2, 3, 9, 5.10.4.1, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, 3.4.8, CCI-001749, 164.308(a)(1)(ii)(D), 164.312(b), 164.312(c)(1), 164.312(c)(2), 164.312(e)(2)(i), 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), SA-12, SA-12(10), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, FPT_TUD_EXT.1, FPT_TUD_EXT.2, Req-6.2, 6.3.3, SRG-OS-000366-GPOS-00153

Remediation Shell script ⇲

    sed -i 's/gpgcheck\s*=.*/gpgcheck=1/g' /etc/yum.repos.d/*

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | enable

    - name: Grep for yum repo section names
      shell: |
        set -o pipefail
        grep -HEr '^\[.+\]' -r /etc/yum.repos.d/
      register: repo_grep_results
      failed_when: repo_grep_results.rc not in [0, 1]
      changed_when: false
      tags:
      - CJIS-5.10.4.1
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SI-7
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-6.3.3
      - enable_strategy
      - ensure_gpgcheck_never_disabled
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed

    - name: Set gpgcheck=1 for each yum repo
      ini_file:
        path: '{{ item[0] }}'
        section: '{{ item[1] }}'
        option: gpgcheck
        value: '1'
        no_extra_spaces: true
      loop: '{{ repo_grep_results.stdout | regex_findall( ''(.+\.repo):\[(.+)\]\n?'' )
        }}'
      tags:
      - CJIS-5.10.4.1
      - NIST-800-171-3.4.8
      - NIST-800-53-CM-11(a)
      - NIST-800-53-CM-11(b)
      - NIST-800-53-CM-5(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SA-12
      - NIST-800-53-SA-12(10)
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SI-7
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-6.3.3
      - enable_strategy
      - ensure_gpgcheck_never_disabled
      - high_severity
      - low_complexity
      - medium_disruption
      - no_reboot_needed

#### Rule Ensure Oracle Linux GPG Key Installed [ref]

To ensure the system can cryptographically verify base software packages come from Oracle (and to connect to the Unbreakable Linux Network to receive them), the Oracle GPG key must properly be installed. To install the Oracle GPG key, run:

    $ sudo uln_register

If the system is not connected to the Internet, then install the Oracle GPG key from trusted media such as the Oracle installation CD-ROM or DVD. Assuming the disc is mounted in `/media/cdrom`, use the following command as the root user to import it into the keyring:

    $ sudo rpm --import /media/cdrom/RPM-GPG-KEY-oracle

Alternatively, the key may be pre-loaded during the Oracle installation. In such cases, the key can be installed by running the following command:

    sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-oracle

Rationale: | Changes to software components can have significant effects on the overall security of the operating system. This requirement ensures the software has not been tampered with and that it has been provided by a trusted vendor. The Oracle GPG key is necessary to cryptographically verify packages are from Oracle.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_ensure_oracle_gpgkey_installed

Identifiers and References

References: 11, 2, 3, 9, APO01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS06.02, CCI-001749, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.4, SR 3.1, SR 3.3, SR 3.4, SR 3.8, SR 7.6, A.11.2.4, A.12.1.2, A.12.2.1, A.12.5.1, A.12.6.2, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, CM-5(3), SI-7, SC-12, SC-12(3), CM-6(a), CM-11(a), CM-11(b), PR.DS-6, PR.DS-8, PR.IP-1, Req-6.2, OL07-00-010019, 1.2.2, SV-256975r902762_rule

Remediation Shell script ⇲

    # OL fingerprints below retrieved from: https://linux.oracle.com/security/gpg/#gpg
    readonly OL_RELEASE_FINGERPRINT="42144123FECFC55B9086313D72F97B74EC551F03"
    readonly OL_AUXILIARY_FINGERPRINT=""

    FINGERPRINTS_REGEX="${OL_RELEASE_FINGERPRINT}"

    if [[ -n "$OL_AUXILIARY_FINGERPRINT" ]]; then
        FINGERPRINTS_REGEX+="|${OL_AUXILIARY_FINGERPRINT}"
    fi

    # Location of the key we would like to import (once it's integrity verified)
    readonly OL_RELEASE_KEY="/etc/pki/rpm-gpg/RPM-GPG-KEY-oracle"

    RPM_GPG_DIR_PERMS=$(stat -c %a "$(dirname "$OL_RELEASE_KEY")")

    # Verify /etc/pki/rpm-gpg directory permissions are safe
    if [ "${RPM_GPG_DIR_PERMS}" -le "755" ]
    then
      # If they are safe, try to obtain fingerprints from the key file
      # (to ensure there won't be e.g. CRC error)

        readarray -t GPG_OUT < <(gpg --with-fingerprint --with-colons "$OL_RELEASE_KEY" | grep "^fpr" | cut -d ":" -f 10)

      GPG_RESULT=$?
      # No CRC error, safe to proceed
      if [ "${GPG_RESULT}" -eq "0" ]
      then
        # Filter just hexadecimal fingerprints from gpg's output from
        # processing of a key file
        echo "${GPG_OUT[*]}" | grep -vE "$FINGERPRINTS_REGEX" || {
          # If $ OL_RELEASE_KEY file doesn't contain any keys with unknown fingerprint, import it
          rpm --import "${OL_RELEASE_KEY}"
        }
      fi
    fi

#### Rule Ensure Software Patches Installed [ref]

If the system is joined to the ULN or a yum server, run the following command to install updates:

    $ sudo yum update

If the system is not configured to use one of these sources, updates (in the form of RPM packages) can be manually downloaded from the ULN and installed using `rpm`.
NOTE: U.S. Defense systems are required to be patched within 30 days or sooner as local policy dictates.
Warning: The OVAL feed of Oracle Linux 7 is not a XML file, which may not be understood by all scanners.

Rationale: | Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities. If the most recent security patches and updates are not installed, unauthorized users may take advantage of weaknesses in the unpatched software. The lack of prompt attention to patching could result in a system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_security_patches_up_to_date
Identifiers and References | References: BP28(R08), 18, 20, 4, 5.10.4.1, APO12.01, APO12.02, APO12.03, APO12.04, BAI03.10, DSS05.01, DSS05.02, CCI-000366, CCI-001227, 4.2.3, 4.2.3.12, 4.2.3.7, 4.2.3.9, A.12.6.1, A.14.2.3, A.16.1.3, A.18.2.2, A.18.2.3, SI-2(5), SI-2(c), CM-6(a), ID.RA-1, PR.IP-12, FMT_MOF_EXT.1, Req-6.2, 6.3.3, SRG-OS-000480-GPOS-00227, OL07-00-020260, SV-221720r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | high
Reboot: | true
Strategy: | patch

    yum -y update

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | true
Strategy: | patch

    - name: Security patches are up to date
      package:
        name: '*'
        state: latest
      tags:
      - CJIS-5.10.4.1
      - DISA-STIG-OL07-00-020260
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-2(5)
      - NIST-800-53-SI-2(c)
      - PCI-DSS-Req-6.2
      - PCI-DSSv4-6.3.3
      - high_disruption
      - low_complexity
      - medium_severity
      - patch_strategy
      - reboot_required
      - security_patches_up_to_date
      - skip_ansible_lint

Group Account and Access Control Group contains 18 groups and 53 rules

[ref] In traditional Unix security, if an attacker gains shell access to a certain login account, they can perform any action or access any file to which that account has access. Therefore, making it more difficult for unauthorized people to gain shell access to accounts, particularly to privileged accounts, is a necessary part of securing a system. This section introduces mechanisms for restricting access to accounts under Oracle Linux 7.

Group Warning Banners for System Accesses Group contains 1 group and 3 rules

[ref] Each system should expose as little information about itself as possible.
System banners, which are typically displayed just before a login prompt, give out information about the service or the host's operating system. This might include the distribution name and the system kernel version, and the particular version of a network service. This information can assist intruders in gaining access to the system as it can reveal whether the system is running vulnerable software. Most network services can be configured to limit what information is displayed.
Many organizations implement security policies that require a system banner provide notice of the system's ownership, provide warning to unauthorized users, and remind authorized users of their consent to monitoring.

Group Implement a GUI Warning Banner Group contains 2 rules
[ref] In the default graphical environment, users logging directly into the system are greeted with a login screen provided by the GNOME Display Manager (GDM). The warning banner should be displayed in this graphical environment for these users. The following sections describe how to configure the GDM login banner.

#### Rule Enable GNOME3 Login Warning Banner [ref]

In the default graphical environment, displaying a login warning banner in the GNOME Display Manager's login screen can be enabled on the login screen by setting `banner-message-enable` to `true`.
To enable, add or edit `banner-message-enable` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    banner-message-enable=true

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/banner-message-enable

After the settings have been set, run `dconf update`. The banner text must also be set.

Rationale:

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
For U.S. Government systems, system use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_banner_enabled

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(b), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, OL07-00-010030, SV-221654r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm; then

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*banner-message-enable\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)banner-message-enable(\s*=)/#\1banner-message-enable\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "true")"
    if grep -q "^\\s*banner-message-enable\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*banner-message-enable\\s*=\\s*.*/banner-message-enable=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-enable=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-enable$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/banner-message-enable$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/banner-message-enable$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/banner-message-enable" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010030
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(b)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_banner_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Enable GNOME3 Login Warning Banner
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: banner-message-enable
        value: 'true'
        create: true
        no_extra_spaces: true
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010030
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(b)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_banner_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of GNOME banner-message-enabled
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/banner-message-enable$
        line: /org/gnome/login-screen/banner-message-enable
        create: true
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010030
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(b)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_banner_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010030
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(b)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_banner_enabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Set the GNOME3 Login Warning Banner Text [ref]

In the default graphical environment, configuring the login warning banner text in the GNOME Display Manager's login screen can be configured on the login screen by setting `banner-message-text` to `'APPROVED_BANNER'` where APPROVED_BANNER is the approved banner for your environment.
To enable, add or edit `banner-message-text` to `/etc/dconf/db/local.d/00-security-settings`. For example:

    [org/gnome/login-screen]
    banner-message-text='APPROVED_BANNER'

Once the setting has been added, add a lock to `/etc/dconf/db/local.d/locks/00-security-settings-lock` to prevent user modification. For example:

    /org/gnome/login-screen/banner-message-text

After the settings have been set, run `dconf update`. When entering a warning banner that spans several lines, remember to begin and end the string with `'` and use `\n` for new lines.

Rationale: | An appropriate warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dconf_gnome_login_banner_text

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, OL07-00-010040, SV-221655r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q gdm; then

    login_banner_text='^\-\-[\s\n]+WARNING[\s\n]+\-\-[\s\n]+This[\s\n]+system[\s\n]+is[\s\n]+for[\s\n]+the[\s\n]+use[\s\n]+of[\s\n]+authorized[\s\n]+users[\s\n]+only\.[\s\n]+Individuals[\s\n]+using[\s\n]+this[\s\n]+computer[\s\n]+system[\s\n]+without[\s\n]+authority[\s\n]+or[\s\n]+in[\s\n]+excess[\s\n]+of[\s\n]+their[\s\n]+authority[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+having[\s\n]+all[\s\n]+their[\s\n]+activities[\s\n]+on[\s\n]+this[\s\n]+system[\s\n]+monitored[\s\n]+and[\s\n]+recorded[\s\n]+by[\s\n]+system[\s\n]+personnel\.[\s\n]+Anyone[\s\n]+using[\s\n]+this[\s\n]+system[\s\n]+expressly[\s\n]+consents[\s\n]+to[\s\n]+such[\s\n]+monitoring[\s\n]+and[\s\n]+is[\s\n]+advised[\s\n]+that[\s\n]+if[\s\n]+such[\s\n]+monitoring[\s\n]+reveals[\s\n]+possible[\s\n]+evidence[\s\n]+of[\s\n]+criminal[\s\n]+activity[\s\n]+system[\s\n]+personal[\s\n]+may[\s\n]+provide[\s\n]+the[\s\n]+evidence[\s\n]+of[\s\n]+such[\s\n]+monitoring[\s\n]+to[\s\n]+law[\s\n]+enforcement[\s\n]+officials\.$'

    # Multiple regexes transform the banner regex into a usable banner
    # 0 - Remove anchors around the banner text
    login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
    # 1 - Keep only the first banners if there are multiple
    #    (dod_banners contains the long and short banner)
    login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
    # 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
    login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
    # 3 - Adds newline "tokens". (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "(n)*")
    login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/(n)*/g')
    # 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
    login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
    # 5 - Removes the newline "token." (Transforms them into newline escape sequences "\n").
    #    ( Needs to be done after 4, otherwise the escapce sequence will become just "n".
    login_banner_text=$(echo "$login_banner_text" | sed 's/(n)\*/\\n/g')

    # Check for setting in any of the DConf db directories
    # If files contain ibus or distro, ignore them.
    # The assignment assumes that individual filenames don't contain :
    readarray -t SETTINGSFILES < <(grep -r "\\[org/gnome/login-screen\\]" "/etc/dconf/db/" \
                                    | grep -v 'distro\|ibus\|local.d' | cut -d":" -f1)
    DCONFFILE="/etc/dconf/db/local.d/00-security-settings"
    DBDIR="/etc/dconf/db/local.d"

    mkdir -p "${DBDIR}"

    # Comment out the configurations in databases different from the target one
    if [ "${#SETTINGSFILES[@]}" -ne 0 ]
    then
        if grep -q "^\\s*banner-message-text\\s*=" "${SETTINGSFILES[@]}"
        then

            sed -Ei "s/(^\s*)banner-message-text(\s*=)/#\1banner-message-text\2/g" "${SETTINGSFILES[@]}"
        fi
    fi

    [ ! -z "${DCONFFILE}" ] && echo "" >> "${DCONFFILE}"
    if ! grep -q "\\[org/gnome/login-screen\\]" "${DCONFFILE}"
    then
        printf '%s\n' "[org/gnome/login-screen]" >> ${DCONFFILE}
    fi

    escaped_value="$(sed -e 's/\\/\\\\/g' <<< "'${login_banner_text}'")"
    if grep -q "^\\s*banner-message-text\\s*=" "${DCONFFILE}"
    then
            sed -i "s/\\s*banner-message-text\\s*=\\s*.*/banner-message-text=${escaped_value}/g" "${DCONFFILE}"
        else
            sed -i "\\|\\[org/gnome/login-screen\\]|a\\banner-message-text=${escaped_value}" "${DCONFFILE}"
    fi

    dconf update
    # Check for setting in any of the DConf db directories
    LOCKFILES=$(grep -r "^/org/gnome/login-screen/banner-message-text$" "/etc/dconf/db/" \
                | grep -v 'distro\|ibus\|local.d' | grep ":" | cut -d":" -f1)
    LOCKSFOLDER="/etc/dconf/db/local.d/locks"

    mkdir -p "${LOCKSFOLDER}"

    # Comment out the configurations in databases different from the target one
    if [[ ! -z "${LOCKFILES}" ]]
    then
        sed -i -E "s|^/org/gnome/login-screen/banner-message-text$|#&|" "${LOCKFILES[@]}"
    fi

    if ! grep -qr "^/org/gnome/login-screen/banner-message-text$" /etc/dconf/db/local.d/
    then
        echo "/org/gnome/login-screen/banner-message-text" >> "/etc/dconf/db/local.d/locks/00-security-settings-lock"
    fi

    dconf update

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
    - name: XCCDF Value login_banner_text # promote to variable
      set_fact:
        login_banner_text: !!str ^\-\-[\s\n]+WARNING[\s\n]+\-\-[\s\n]+This[\s\n]+system[\s\n]+is[\s\n]+for[\s\n]+the[\s\n]+use[\s\n]+of[\s\n]+authorized[\s\n]+users[\s\n]+only\.[\s\n]+Individuals[\s\n]+using[\s\n]+this[\s\n]+computer[\s\n]+system[\s\n]+without[\s\n]+authority[\s\n]+or[\s\n]+in[\s\n]+excess[\s\n]+of[\s\n]+their[\s\n]+authority[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+having[\s\n]+all[\s\n]+their[\s\n]+activities[\s\n]+on[\s\n]+this[\s\n]+system[\s\n]+monitored[\s\n]+and[\s\n]+recorded[\s\n]+by[\s\n]+system[\s\n]+personnel\.[\s\n]+Anyone[\s\n]+using[\s\n]+this[\s\n]+system[\s\n]+expressly[\s\n]+consents[\s\n]+to[\s\n]+such[\s\n]+monitoring[\s\n]+and[\s\n]+is[\s\n]+advised[\s\n]+that[\s\n]+if[\s\n]+such[\s\n]+monitoring[\s\n]+reveals[\s\n]+possible[\s\n]+evidence[\s\n]+of[\s\n]+criminal[\s\n]+activity[\s\n]+system[\s\n]+personal[\s\n]+may[\s\n]+provide[\s\n]+the[\s\n]+evidence[\s\n]+of[\s\n]+such[\s\n]+monitoring[\s\n]+to[\s\n]+law[\s\n]+enforcement[\s\n]+officials\.$
      tags:
        - always

    - name: Set the GNOME3 Login Warning Banner Text
      file:
        path: /etc/dconf/db/{{ item }}
        owner: root
        group: root
        mode: 493
        state: directory
      with_items:
      - local.d
      - local.d/locks
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Set the GNOME3 Login Warning Banner Text
      file:
        path: /etc/dconf/db/local.d/{{ item }}
        owner: root
        group: root
        mode: 420
        state: touch
      with_items:
      - 00-security-settings
      - locks/00-security-settings-lock
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Set the GNOME3 Login Warning Banner Text
      ini_file:
        dest: /etc/dconf/db/local.d/00-security-settings
        section: org/gnome/login-screen
        option: banner-message-text
        value: '''{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
          "\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
          "(n)*") | regex_replace("\\", "") | regex_replace("\(n\)\*", "\\n") }}'''
        create: true
        no_extra_spaces: true
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Prevent user modification of the GNOME3 Login Warning Banner Text
      lineinfile:
        path: /etc/dconf/db/local.d/locks/00-security-settings-lock
        regexp: ^/org/gnome/login-screen/banner-message-text$
        line: /org/gnome/login-screen/banner-message-text
        create: true
        state: present
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

    - name: Dconf Update
      command: dconf update
      when: '"gdm" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010040
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - dconf_gnome_login_banner_text
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

#### Rule Modify the System Login Banner [ref]

To configure the system login banner edit `/etc/issue`. Replace the default text with a message compliant with the local site policy or a legal disclaimer. The DoD required text is either:
`You are accessing a U.S. Government (USG) Information System (IS) that is provided for USG-authorized use only. By using this IS (which includes any device attached to this IS), you consent to the following conditions:
-The USG routinely intercepts and monitors communications on this IS for purposes including, but not limited to, penetration testing, COMSEC monitoring, network operations and defense, personnel misconduct (PM), law enforcement (LE), and counterintelligence (CI) investigations.
-At any time, the USG may inspect and seize data stored on this IS.
-Communications using, or data stored on, this IS are not private, are subject to routine monitoring, interception, and search, and may be disclosed or used for any USG-authorized purpose.
-This IS includes security measures (e.g., authentication and access controls) to protect USG interests -- not for your personal benefit or privacy.
-Notwithstanding the above, using this IS does not constitute consent to PM, LE or CI investigative searching or monitoring of the content of privileged communications, or work product, related to personal representation or services by attorneys, psychotherapists, or clergy, and their assistants. Such communications and work product are private and confidential. See User Agreement for details.`
OR:
`I've read & consent to terms in IS user agreem't.`

Rationale:

Display of a standardized and approved use notification before granting access to the operating system ensures privacy and security notification verbiage used is consistent with applicable federal laws, Executive Orders, directives, policies, regulations, standards, and guidance.
System use notifications are required only for access via login interfaces with human users and are not required when such human interfaces do not exist.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_banner_etc_issue

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, OL07-00-010050, SV-221656r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    login_banner_text='^\-\-[\s\n]+WARNING[\s\n]+\-\-[\s\n]+This[\s\n]+system[\s\n]+is[\s\n]+for[\s\n]+the[\s\n]+use[\s\n]+of[\s\n]+authorized[\s\n]+users[\s\n]+only\.[\s\n]+Individuals[\s\n]+using[\s\n]+this[\s\n]+computer[\s\n]+system[\s\n]+without[\s\n]+authority[\s\n]+or[\s\n]+in[\s\n]+excess[\s\n]+of[\s\n]+their[\s\n]+authority[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+having[\s\n]+all[\s\n]+their[\s\n]+activities[\s\n]+on[\s\n]+this[\s\n]+system[\s\n]+monitored[\s\n]+and[\s\n]+recorded[\s\n]+by[\s\n]+system[\s\n]+personnel\.[\s\n]+Anyone[\s\n]+using[\s\n]+this[\s\n]+system[\s\n]+expressly[\s\n]+consents[\s\n]+to[\s\n]+such[\s\n]+monitoring[\s\n]+and[\s\n]+is[\s\n]+advised[\s\n]+that[\s\n]+if[\s\n]+such[\s\n]+monitoring[\s\n]+reveals[\s\n]+possible[\s\n]+evidence[\s\n]+of[\s\n]+criminal[\s\n]+activity[\s\n]+system[\s\n]+personal[\s\n]+may[\s\n]+provide[\s\n]+the[\s\n]+evidence[\s\n]+of[\s\n]+such[\s\n]+monitoring[\s\n]+to[\s\n]+law[\s\n]+enforcement[\s\n]+officials\.$'

    # Multiple regexes transform the banner regex into a usable banner
    # 0 - Remove anchors around the banner text
    login_banner_text=$(echo "$login_banner_text" | sed 's/^\^\(.*\)\$$/\1/g')
    # 1 - Keep only the first banners if there are multiple
    #    (dod_banners contains the long and short banner)
    login_banner_text=$(echo "$login_banner_text" | sed 's/^(\(.*\.\)|.*)$/\1/g')
    # 2 - Add spaces ' '. (Transforms regex for "space or newline" into a " ")
    login_banner_text=$(echo "$login_banner_text" | sed 's/\[\\s\\n\]+/ /g')
    # 3 - Adds newlines. (Transforms "(?:\[\\n\]+|(?:\\n)+)" into "\n")
    login_banner_text=$(echo "$login_banner_text" | sed 's/(?:\[\\n\]+|(?:\\\\n)+)/\n/g')
    # 4 - Remove any leftover backslash. (From any parethesis in the banner, for example).
    login_banner_text=$(echo "$login_banner_text" | sed 's/\\//g')
    formatted=$(echo "$login_banner_text" | fold -sw 80)
    cat <<EOF >/etc/issue
    $formatted
    EOF

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: XCCDF Value login_banner_text # promote to variable
      set_fact:
        login_banner_text: !!str ^\-\-[\s\n]+WARNING[\s\n]+\-\-[\s\n]+This[\s\n]+system[\s\n]+is[\s\n]+for[\s\n]+the[\s\n]+use[\s\n]+of[\s\n]+authorized[\s\n]+users[\s\n]+only\.[\s\n]+Individuals[\s\n]+using[\s\n]+this[\s\n]+computer[\s\n]+system[\s\n]+without[\s\n]+authority[\s\n]+or[\s\n]+in[\s\n]+excess[\s\n]+of[\s\n]+their[\s\n]+authority[\s\n]+are[\s\n]+subject[\s\n]+to[\s\n]+having[\s\n]+all[\s\n]+their[\s\n]+activities[\s\n]+on[\s\n]+this[\s\n]+system[\s\n]+monitored[\s\n]+and[\s\n]+recorded[\s\n]+by[\s\n]+system[\s\n]+personnel\.[\s\n]+Anyone[\s\n]+using[\s\n]+this[\s\n]+system[\s\n]+expressly[\s\n]+consents[\s\n]+to[\s\n]+such[\s\n]+monitoring[\s\n]+and[\s\n]+is[\s\n]+advised[\s\n]+that[\s\n]+if[\s\n]+such[\s\n]+monitoring[\s\n]+reveals[\s\n]+possible[\s\n]+evidence[\s\n]+of[\s\n]+criminal[\s\n]+activity[\s\n]+system[\s\n]+personal[\s\n]+may[\s\n]+provide[\s\n]+the[\s\n]+evidence[\s\n]+of[\s\n]+such[\s\n]+monitoring[\s\n]+to[\s\n]+law[\s\n]+enforcement[\s\n]+officials\.$
      tags:
        - always

    - name: Modify the System Login Banner - Ensure Correct Banner
      copy:
        dest: /etc/issue
        content: '{{ login_banner_text | regex_replace("^\^(.*)\$$", "\1") | regex_replace("^\((.*\.)\|.*\)$",
          "\1") | regex_replace("\[\\s\\n\]\+"," ") | regex_replace("\(\?:\[\\n\]\+\|\(\?:\\\\n\)\+\)",
          "\n") | regex_replace("\\", "") | wordwrap() }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010050
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - banner_etc_issue
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy

Group Protect Accounts by Configuring PAM Group contains 4 groups and 19 rules

[ref] PAM, or Pluggable Authentication Modules, is a system which implements modular authentication for Linux programs. PAM provides a flexible and configurable architecture for authentication, and it should be configured to minimize exposure to unnecessary risk. This section contains guidance on how to accomplish that.
PAM is implemented as a set of shared objects which are loaded and invoked whenever an application wishes to authenticate a user. Typically, the application must be running as root in order to take advantage of PAM, because PAM's modules often need to be able to access sensitive stores of account information, such as /etc/shadow. Traditional privileged network listeners (e.g. sshd) or SUID programs (e.g. sudo) already meet this requirement. An SUID root application, userhelper, is provided so that programs which are not SUID or privileged themselves can still take advantage of PAM.
PAM looks in the directory `/etc/pam.d` for application-specific configuration information. For instance, if the program login attempts to authenticate a user, then PAM's libraries follow the instructions in the file `/etc/pam.d/login` to determine what actions should be taken.
One very important file in `/etc/pam.d` is `/etc/pam.d/system-auth`. This file, which is included by many other PAM configuration files, defines 'default' system authentication measures. Modifying this file is a good way to make far-reaching authentication changes, for instance when implementing a centralized authentication service.
Warning: Be careful when making changes to PAM's configuration files. The syntax for these files is complex, and modifications can have unexpected consequences. The default configurations shipped with applications should be sufficient for most users.
Warning: Running `authconfig` or `system-config-authentication` will re-write the PAM configuration files, destroying any manually made changes and replacing them with a series of system defaults. One reference to the configuration file syntax can be found at https://fossies.org/linux/Linux-PAM-docs/doc/sag/Linux-PAM_SAG.pdf.

Group Set Lockouts for Failed Password Attempts Group contains 5 rules

[ref] The `pam_faillock` PAM module provides the capability to lock out user accounts after a number of failed login attempts. Its documentation is available in `/usr/share/doc/pam-VERSION/txts/README.pam_faillock`.
Warning: Locking out user accounts presents the risk of a denial-of-service attack. The lockout policy must weigh whether the risk of such a denial-of-service attack outweighs the benefits of thwarting password guessing attacks.

#### Rule Limit Password Reuse [ref]

Do not allow users to reuse recent passwords. This can be accomplished by using the `remember` option for the `pam_unix` or `pam_pwhistory` PAM modules.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report.
Warning: Newer versions of `authselect` contain an authselect feature to easily and properly enable `pam_pwhistory.so` module. If this feature is not yet available in your system, an authselect custom profile must be used to avoid integrity issues in PAM files.

Rationale: | Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_unix_remember

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000200, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(e), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.5, 8.3.7, SRG-OS-000077-GPOS-00045

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_unix_remember='5'

    if [ -f /usr/bin/authselect ]; then
        if authselect list-features minimal | grep -q with-pwhistory; then
            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi
            authselect enable-feature with-pwhistory

            authselect apply-changes -b
        else

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
            if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
                # Line matching group + control + module was not found. Check group + module.
                if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                    # The control is updated only if one single line matches.
                    sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
                else
                    LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                    if [ ! -z $LAST_MATCH_LINE ]; then
                        sed -i --follow-symlinks $LAST_MATCH_LINE' a password     '"requisite"'    pam_pwhistory.so' "$PAM_FILE_PATH"
                    else
                        echo 'password    '"requisite"'    pam_pwhistory.so' >> "$PAM_FILE_PATH"
                    fi
                fi
            fi
        fi
    else
        if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "/etc/pam.d/system-auth"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "/etc/pam.d/system-auth")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "/etc/pam.d/system-auth"
            else
                LAST_MATCH_LINE=$(grep -nP "^password.*requisite.*pam_pwquality\.so" "/etc/pam.d/system-auth" | tail -n 1 | cut -d: -f 1)
                if [ ! -z $LAST_MATCH_LINE ]; then
                    sed -i --follow-symlinks $LAST_MATCH_LINE' a password     '"requisite"'    pam_pwhistory.so' "/etc/pam.d/system-auth"
                else
                    echo 'password    '"requisite"'    pam_pwhistory.so' >> "/etc/pam.d/system-auth"
                fi
            fi
        fi
    fi

    PWHISTORY_CONF="/etc/security/pwhistory.conf"
    if [ -f $PWHISTORY_CONF ]; then
        regex="^\s*remember\s*="
        line="remember = $var_password_pam_unix_remember"
        if ! grep -q $regex $PWHISTORY_CONF; then
            echo $line >> $PWHISTORY_CONF
        else
            sed -i --follow-symlinks 's|^\s*\(remember\s*=\s*\)\(\S\+\)|\1'"$var_password_pam_unix_remember"'|g' $PWHISTORY_CONF
        fi
        if [ -e "/etc/pam.d/system-auth" ] ; then
            PAM_FILE_PATH="/etc/pam.d/system-auth"
            if [ -f /usr/bin/authselect ]; then

                if ! authselect check; then
                echo "
                authselect integrity check failed. Remediation aborted!
                This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                It is not recommended to manually edit the PAM files when authselect tool is available.
                In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                exit 1
                fi

                CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                # If not already in use, a custom profile is created preserving the enabled features.
                if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                    ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                    authselect create-profile hardening -b $CURRENT_PROFILE
                    CURRENT_PROFILE="custom/hardening"

                    authselect apply-changes -b --backup=before-hardening-custom-profile
                    authselect select $CURRENT_PROFILE
                    for feature in $ENABLED_FEATURES; do
                        authselect enable-feature $feature;
                    done

                    authselect apply-changes -b --backup=after-hardening-custom-profile
                fi
                PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
                PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                authselect apply-changes -b
            fi

        if grep -qP '^\s*password\s.*\bpam_pwhistory.so\s.*\bremember\b' "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks 's/(.*password.*pam_pwhistory.so.*)\bremember\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
        fi
            if [ -f /usr/bin/authselect ]; then

                authselect apply-changes -b
            fi
        else
            echo "/etc/pam.d/system-auth was not found" >&2
        fi
    else
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi
        if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*' "$PAM_FILE_PATH"; then
            # Line matching group + control + module was not found. Check group + module.
            if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwhistory.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                # The control is updated only if one single line matches.
                sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwhistory.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
            else
                echo 'password    '"requisite"'    pam_pwhistory.so' >> "$PAM_FILE_PATH"
            fi
        fi
        # Check the option
        if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwhistory.so\s*.*\sremember\b' "$PAM_FILE_PATH"; then
            sed -i -E --follow-symlinks '/\s*password\s+'"requisite"'\s+pam_pwhistory.so.*/ s/$/ remember='"$var_password_pam_unix_remember"'/' "$PAM_FILE_PATH"
        else
            sed -i -E --follow-symlinks 's/(\s*password\s+'"requisite"'\s+pam_pwhistory.so\s+.*)('"remember"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_unix_remember"' \3/' "$PAM_FILE_PATH"
        fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
    - name: XCCDF Value var_password_pam_unix_remember # promote to variable
      set_fact:
        var_password_pam_unix_remember: !!str 5
      tags:
        - always

    - name: Limit Password Reuse - Check if system relies on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - Collect the available authselect features
      ansible.builtin.command:
        cmd: authselect list-features minimal
      register: result_authselect_available_features
      changed_when: false
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - Enable pam_pwhistory.so using authselect feature
      block:

      - name: Limit Password Reuse - Check integrity of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Limit Password Reuse - Informative message based on the authselect integrity
          check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Limit Password Reuse - Get authselect current features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Limit Password Reuse - Ensure "with-pwhistory" feature is enabled using
          authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature with-pwhistory
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("with-pwhistory")

      - name: Limit Password Reuse - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      - result_authselect_available_features.stdout is search("with-pwhistory")
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - Enable pam_pwhistory.so in appropriate PAM files
      block:

      - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Limit Password Reuse - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
          is present
        block:

        - name: Limit Password Reuse - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Limit Password Reuse - Informative message based on the authselect integrity
            check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Limit Password Reuse - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Limit Password Reuse - Define the current authselect profile as a local
            fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Limit Password Reuse - Define the new authselect custom profile as a local
            fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Limit Password Reuse - Get authselect current features to also enable
            them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Check if any custom profile with the same name
            was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Create an authselect custom profile based on the
            current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Limit Password Reuse - Change the PAM file to be edited according to the
            custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Limit Password Reuse - Check if expected PAM module line is present in {{
          pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_line_present

      - name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
          }}
        block:

        - name: Limit Password Reuse - Check if required PAM module line is present in
            {{ pam_file_path }} with different control
          ansible.builtin.lineinfile:
            path: '{{ pam_file_path }}'
            regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
            state: absent
          check_mode: true
          changed_when: false
          register: result_pam_line_other_control_present

        - name: Limit Password Reuse - Ensure the correct control for the required PAM
            module line in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
            replace: \1requisite \2
          register: result_pam_module_edit
          when:
          - result_pam_line_other_control_present.found == 1

        - name: Limit Password Reuse - Ensure the required PAM module line is included
            in {{ pam_file_path }}
          ansible.builtin.lineinfile:
            dest: '{{ pam_file_path }}'
            insertafter: ^password.*requisite.*pam_pwquality\.so
            line: password    requisite    pam_pwhistory.so
          register: result_pam_module_add
          when:
          - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
            > 1

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present is defined
          - result_authselect_present.stat.exists
          - |-
            (result_pam_module_add is defined and result_pam_module_add.changed)
             or (result_pam_module_edit is defined and result_pam_module_edit.changed)
        when:
        - result_pam_line_present.found is defined
        - result_pam_line_present.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - |
        (result_authselect_available_features.stdout is defined and result_authselect_available_features.stdout is not search("with-pwhistory")) or result_authselect_available_features is not defined
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - Check the presence of /etc/security/pwhistory.conf
        file
      ansible.builtin.stat:
        path: /etc/security/pwhistory.conf
      register: result_pwhistory_conf_check
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - pam_pwhistory.so parameters are configured in /etc/security/pwhistory.conf
        file
      block:

      - name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter in
          /etc/security/pwhistory.conf
        ansible.builtin.lineinfile:
          path: /etc/security/pwhistory.conf
          regexp: ^\s*remember\s*=
          line: remember = {{ var_password_pam_unix_remember }}
          state: present

      - name: Limit Password Reuse - Ensure the pam_pwhistory.so remember parameter is
          removed from PAM files
        block:

        - name: Limit Password Reuse - Check if /etc/pam.d/system-auth file is present
          ansible.builtin.stat:
            path: /etc/pam.d/system-auth
          register: result_pam_file_present

        - name: Limit Password Reuse - Check the proper remediation for the system
          block:

          - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
            ansible.builtin.set_fact:
              pam_file_path: /etc/pam.d/system-auth

          - name: Limit Password Reuse - Check if system relies on authselect tool
            ansible.builtin.stat:
              path: /usr/bin/authselect
            register: result_authselect_present

          - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
              is present
            block:

            - name: Limit Password Reuse - Check integrity of authselect current profile
              ansible.builtin.command:
                cmd: authselect check
              register: result_authselect_check_cmd
              changed_when: false
              failed_when: false

            - name: Limit Password Reuse - Informative message based on the authselect
                integrity check result
              ansible.builtin.assert:
                that:
                - result_authselect_check_cmd.rc == 0
                fail_msg:
                - authselect integrity check failed. Remediation aborted!
                - This remediation could not be applied because an authselect profile
                  was not selected or the selected profile is not intact.
                - It is not recommended to manually edit the PAM files when authselect
                  tool is available.
                - In cases where the default authselect profile does not cover a specific
                  demand, a custom authselect profile is recommended.
                success_msg:
                - authselect integrity check passed

            - name: Limit Password Reuse - Get authselect current profile
              ansible.builtin.shell:
                cmd: authselect current -r | awk '{ print $1 }'
              register: result_authselect_profile
              changed_when: false
              when:
              - result_authselect_check_cmd is success

            - name: Limit Password Reuse - Define the current authselect profile as a
                local fact
              ansible.builtin.set_fact:
                authselect_current_profile: '{{ result_authselect_profile.stdout }}'
                authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
              when:
              - result_authselect_profile is not skipped
              - result_authselect_profile.stdout is match("custom/")

            - name: Limit Password Reuse - Define the new authselect custom profile as
                a local fact
              ansible.builtin.set_fact:
                authselect_current_profile: '{{ result_authselect_profile.stdout }}'
                authselect_custom_profile: custom/hardening
              when:
              - result_authselect_profile is not skipped
              - result_authselect_profile.stdout is not match("custom/")

            - name: Limit Password Reuse - Get authselect current features to also enable
                them in the custom profile
              ansible.builtin.shell:
                cmd: authselect current | tail -n+3 | awk '{ print $2 }'
              register: result_authselect_features
              changed_when: false
              when:
              - result_authselect_profile is not skipped
              - authselect_current_profile is not match("custom/")

            - name: Limit Password Reuse - Check if any custom profile with the same name
                was already created
              ansible.builtin.stat:
                path: /etc/authselect/{{ authselect_custom_profile }}
              register: result_authselect_custom_profile_present
              changed_when: false
              when:
              - authselect_current_profile is not match("custom/")

            - name: Limit Password Reuse - Create an authselect custom profile based on
                the current profile
              ansible.builtin.command:
                cmd: authselect create-profile hardening -b {{ authselect_current_profile
                  }}
              when:
              - result_authselect_check_cmd is success
              - authselect_current_profile is not match("custom/")
              - not result_authselect_custom_profile_present.stat.exists

            - name: Limit Password Reuse - Ensure authselect changes are applied
              ansible.builtin.command:
                cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
              when:
              - result_authselect_check_cmd is success
              - result_authselect_profile is not skipped
              - authselect_current_profile is not match("custom/")
              - authselect_custom_profile is not match(authselect_current_profile)

            - name: Limit Password Reuse - Ensure the authselect custom profile is selected
              ansible.builtin.command:
                cmd: authselect select {{ authselect_custom_profile }}
              register: result_pam_authselect_select_profile
              when:
              - result_authselect_check_cmd is success
              - result_authselect_profile is not skipped
              - authselect_current_profile is not match("custom/")
              - authselect_custom_profile is not match(authselect_current_profile)

            - name: Limit Password Reuse - Restore the authselect features in the custom
                profile
              ansible.builtin.command:
                cmd: authselect enable-feature {{ item }}
              loop: '{{ result_authselect_features.stdout_lines }}'
              register: result_pam_authselect_restore_features
              when:
              - result_authselect_profile is not skipped
              - result_authselect_features is not skipped
              - result_pam_authselect_select_profile is not skipped

            - name: Limit Password Reuse - Ensure authselect changes are applied
              ansible.builtin.command:
                cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
              when:
              - result_authselect_check_cmd is success
              - result_authselect_profile is not skipped
              - result_pam_authselect_restore_features is not skipped

            - name: Limit Password Reuse - Change the PAM file to be edited according
                to the custom authselect profile
              ansible.builtin.set_fact:
                pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                  | basename }}
            when:
            - result_authselect_present.stat.exists

          - name: Limit Password Reuse - Ensure the "remember" option from "pam_pwhistory.so"
              is not present in {{ pam_file_path }}
            ansible.builtin.replace:
              dest: '{{ pam_file_path }}'
              regexp: (.*password.*pam_pwhistory.so.*)\bremember\b=?[0-9a-zA-Z]*(.*)
              replace: \1\2
            register: result_pam_option_removal

          - name: Limit Password Reuse - Ensure authselect changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b
            when:
            - result_authselect_present.stat.exists
            - result_pam_option_removal is changed
          when:
          - result_pam_file_present.stat.exists
      when:
      - '"pam" in ansible_facts.packages'
      - result_pwhistory_conf_check.stat.exists
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Limit Password Reuse - pam_pwhistory.so parameters are configured in PAM files
      block:

      - name: Limit Password Reuse - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Limit Password Reuse - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Limit Password Reuse - Ensure authselect custom profile is used if authselect
          is present
        block:

        - name: Limit Password Reuse - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Limit Password Reuse - Informative message based on the authselect integrity
            check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Limit Password Reuse - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Limit Password Reuse - Define the current authselect profile as a local
            fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Limit Password Reuse - Define the new authselect custom profile as a local
            fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Limit Password Reuse - Get authselect current features to also enable
            them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Check if any custom profile with the same name
            was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Limit Password Reuse - Create an authselect custom profile based on the
            current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Limit Password Reuse - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Limit Password Reuse - Change the PAM file to be edited according to the
            custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Limit Password Reuse - Check if expected PAM module line is present in {{
          pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_line_present

      - name: Limit Password Reuse - Include or update the PAM module line in {{ pam_file_path
          }}
        block:

        - name: Limit Password Reuse - Check if required PAM module line is present in
            {{ pam_file_path }} with different control
          ansible.builtin.lineinfile:
            path: '{{ pam_file_path }}'
            regexp: ^\s*password\s+.*\s+pam_pwhistory.so\s*
            state: absent
          check_mode: true
          changed_when: false
          register: result_pam_line_other_control_present

        - name: Limit Password Reuse - Ensure the correct control for the required PAM
            module line in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: ^(\s*password\s+).*(\bpam_pwhistory.so.*)
            replace: \1requisite \2
          register: result_pam_module_edit
          when:
          - result_pam_line_other_control_present.found == 1

        - name: Limit Password Reuse - Ensure the required PAM module line is included
            in {{ pam_file_path }}
          ansible.builtin.lineinfile:
            dest: '{{ pam_file_path }}'
            line: password    requisite    pam_pwhistory.so
          register: result_pam_module_add
          when:
          - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
            > 1

        - name: Limit Password Reuse - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present is defined
          - result_authselect_present.stat.exists
          - |-
            (result_pam_module_add is defined and result_pam_module_add.changed)
             or (result_pam_module_edit is defined and result_pam_module_edit.changed)
        when:
        - result_pam_line_present.found is defined
        - result_pam_line_present.found == 0

      - name: Limit Password Reuse - Check if the required PAM module option is present
          in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s*.*\sremember\b
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_module_remember_option_present

      - name: Limit Password Reuse - Ensure the "remember" PAM option for "pam_pwhistory.so"
          is included in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          backrefs: true
          regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so.*)
          line: \1 remember={{ var_password_pam_unix_remember }}
          state: present
        register: result_pam_remember_add
        when:
        - result_pam_module_remember_option_present.found == 0

      - name: Limit Password Reuse - Ensure the required value for "remember" PAM option
          from "pam_pwhistory.so" in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          backrefs: true
          regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwhistory.so\s+.*)(remember)=[0-9a-zA-Z]+\s*(.*)
          line: \1\2={{ var_password_pam_unix_remember }} \3
        register: result_pam_remember_edit
        when:
        - result_pam_module_remember_option_present.found > 0

      - name: Limit Password Reuse - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - (result_pam_remember_add is defined and result_pam_remember_add.changed) or
          (result_pam_remember_edit is defined and result_pam_remember_edit.changed)
      when:
      - '"pam" in ansible_facts.packages'
      - not result_pwhistory_conf_check.stat.exists
      tags:
      - CJIS-5.6.2.1.1
      - NIST-800-171-3.5.8
      - NIST-800-53-IA-5(1)(e)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.5
      - PCI-DSSv4-8.3.7
      - accounts_password_pam_unix_remember
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Lock Accounts After Failed Password Attempts [ref]

This rule configures the system to lock out accounts after a number of incorrect login attempts using `pam_faillock.so`. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. Ensure that the file `/etc/security/faillock.conf` contains the following entry: `deny = <count>` Where count should be less than or equal to 3 and greater than 0. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as `authselect` or `authconfig`, depending on the OS version.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. If the system supports the `/etc/security/faillock.conf` file, the pam_faillock parameters should be defined in `faillock.conf` file.

Rationale: | By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5.5.3, DSS05.04, DSS05.10, DSS06.10, 3.1.8, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), PR.AC-7, FIA_AFL.1, Req-8.1.6, 8.3.4, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010320, SV-221690r880681_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_accounts_passwords_pam_faillock_deny='3'

    if [ -f /usr/bin/authselect ]; then
        if ! authselect check; then
    echo "
    authselect integrity check failed. Remediation aborted!
    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
    It is not recommended to manually edit the PAM files when authselect tool is available.
    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
    exit 1
    fi
    authselect enable-feature with-faillock

    authselect apply-changes -b
    else

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
            sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
            sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
        fi
        sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
    done

    fi

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")

    FAILLOCK_CONF="/etc/security/faillock.conf"
    if [ -f $FAILLOCK_CONF ]; then
        regex="^\s*deny\s*="
        line="deny = $var_accounts_passwords_pam_faillock_deny"
        if ! grep -q $regex $FAILLOCK_CONF; then
            echo $line >> $FAILLOCK_CONF
        else
            sed -i --follow-symlinks 's|^\s*\(deny\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_deny"'|g' $FAILLOCK_CONF
        fi
        for pam_file in "${AUTH_FILES[@]}"
        do
            if [ -e "$pam_file" ] ; then
                PAM_FILE_PATH="$pam_file"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$pam_file")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bdeny\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bdeny\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$pam_file was not found" >&2
            fi
        done
    else
        for pam_file in "${AUTH_FILES[@]}"
        do
            if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*deny' "$pam_file"; then
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ deny='"$var_accounts_passwords_pam_faillock_deny"'/' "$pam_file"
            else
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"deny"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_deny"'\3/' "$pam_file"
            fi
        done
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Check if system relies on authselect
        tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Remediation where authselect
        tool is present
      block:

      - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Lock Accounts After Failed Password Attempts - Informative message based
          on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Lock Accounts After Failed Password Attempts - Get authselect current features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Lock Accounts After Failed Password Attempts - Ensure "with-faillock" feature
          is enabled using authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature with-faillock
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("with-faillock")

      - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Remediation where authselect
        tool is not present
      block:

      - name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
          is already enabled
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail)
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_is_enabled

      - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so preauth
          editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so preauth
          insertbefore: ^auth.*sufficient.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so authfail
          editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so authfail
          insertbefore: ^auth.*required.*pam_deny\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Lock Accounts After Failed Password Attempts - Enable pam_faillock.so account
          section editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: account     required      pam_faillock.so
          insertbefore: ^account.*required.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_passwords_pam_faillock_deny # promote to variable
      set_fact:
        var_accounts_passwords_pam_faillock_deny: !!str 3
      tags:
        - always

    - name: Lock Accounts After Failed Password Attempts - Check the presence of /etc/security/faillock.conf
        file
      ansible.builtin.stat:
        path: /etc/security/faillock.conf
      register: result_faillock_conf_check
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
        deny parameter in /etc/security/faillock.conf
      ansible.builtin.lineinfile:
        path: /etc/security/faillock.conf
        regexp: ^\s*deny\s*=
        line: deny = {{ var_accounts_passwords_pam_faillock_deny }}
        state: present
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
        deny parameter not in PAM files
      block:

      - name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/system-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/system-auth
        register: result_pam_file_present

      - name: Lock Accounts After Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Lock Accounts After Failed Password Attempts - Define the PAM file to
            be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/system-auth

        - name: Lock Accounts After Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
            profile is used if authselect is present
          block:

          - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
              current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Lock Accounts After Failed Password Attempts - Informative message based
              on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Lock Accounts After Failed Password Attempts - Get authselect current
              profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Lock Accounts After Failed Password Attempts - Define the current authselect
              profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Define the new authselect
              custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Get authselect current
              features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Check if any custom profile
              with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Lock Accounts After Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Lock Accounts After Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Lock Accounts After Failed Password Attempts - Change the PAM file to
              be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
            from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
            are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists

      - name: Lock Accounts After Failed Password Attempts - Check if /etc/pam.d/password-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/password-auth
        register: result_pam_file_present

      - name: Lock Accounts After Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Lock Accounts After Failed Password Attempts - Define the PAM file to
            be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/password-auth

        - name: Lock Accounts After Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Lock Accounts After Failed Password Attempts - Ensure authselect custom
            profile is used if authselect is present
          block:

          - name: Lock Accounts After Failed Password Attempts - Check integrity of authselect
              current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Lock Accounts After Failed Password Attempts - Informative message based
              on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Lock Accounts After Failed Password Attempts - Get authselect current
              profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Lock Accounts After Failed Password Attempts - Define the current authselect
              profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Define the new authselect
              custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Get authselect current
              features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Check if any custom profile
              with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Lock Accounts After Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Lock Accounts After Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Lock Accounts After Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Lock Accounts After Failed Password Attempts - Change the PAM file to
              be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Lock Accounts After Failed Password Attempts - Ensure the "deny" option
            from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bdeny\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Lock Accounts After Failed Password Attempts - Ensure authselect changes
            are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Lock Accounts After Failed Password Attempts - Ensure the pam_faillock.so
        deny parameter in PAM files
      block:

      - name: Lock Accounts After Failed Password Attempts - Check if pam_faillock.so
          deny parameter is already enabled in pam files
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail).*deny
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_deny_parameter_is_present

      - name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of pam_faillock.so
          preauth deny parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
          line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_deny_parameter_is_present.found == 0

      - name: Lock Accounts After Failed Password Attempts - Ensure the inclusion of pam_faillock.so
          authfail deny parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
          line: \1required\3 deny={{ var_accounts_passwords_pam_faillock_deny }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_deny_parameter_is_present.found == 0

      - name: Lock Accounts After Failed Password Attempts - Ensure the desired value
          for pam_faillock.so preauth deny parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(deny)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_deny_parameter_is_present.found > 0

      - name: Lock Accounts After Failed Password Attempts - Ensure the desired value
          for pam_faillock.so authfail deny parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(deny)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_deny }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_deny_parameter_is_present.found > 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.6
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_deny
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure the root Account for Failed Password Attempts [ref]

This rule configures the system to lock out the `root` account after a number of incorrect login attempts using `pam_faillock.so`. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as `authselect` or `authconfig`, depending on the OS version.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. If the system supports the `/etc/security/faillock.conf` file, the pam_faillock parameters should be defined in `faillock.conf` file.

Rationale: | By limiting the number of failed logon attempts, the risk of unauthorized system access via user password guessing, also known as brute-forcing, is reduced. Limits are imposed by locking the account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_deny_root

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-002238, CCI-000044, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(b), IA-5(c), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010330, SV-221691r880684_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    if [ -f /usr/bin/authselect ]; then
        if ! authselect check; then
    echo "
    authselect integrity check failed. Remediation aborted!
    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
    It is not recommended to manually edit the PAM files when authselect tool is available.
    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
    exit 1
    fi
    authselect enable-feature with-faillock

    authselect apply-changes -b
    else

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
            sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
            sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
        fi
        sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
    done

    fi

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")

    FAILLOCK_CONF="/etc/security/faillock.conf"
    if [ -f $FAILLOCK_CONF ]; then
        regex="^\s*even_deny_root"
        line="even_deny_root"
        if ! grep -q $regex $FAILLOCK_CONF; then
            echo $line >> $FAILLOCK_CONF
        fi
        for pam_file in "${AUTH_FILES[@]}"
        do
            if [ -e "$pam_file" ] ; then
                PAM_FILE_PATH="$pam_file"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$pam_file")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\beven_deny_root\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$pam_file was not found" >&2
            fi
        done
    else
        for pam_file in "${AUTH_FILES[@]}"
        do
            if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*even_deny_root' "$pam_file"; then
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ even_deny_root/' "$pam_file"
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ even_deny_root/' "$pam_file"
            fi
        done
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Check if system
        relies on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Remediation where
        authselect tool is present
      block:

      - name: Configure the root Account for Failed Password Attempts - Check integrity
          of authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Configure the root Account for Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Configure the root Account for Failed Password Attempts - Get authselect
          current features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Configure the root Account for Failed Password Attempts - Ensure "with-faillock"
          feature is enabled using authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature with-faillock
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("with-faillock")

      - name: Configure the root Account for Failed Password Attempts - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Remediation where
        authselect tool is not present
      block:

      - name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
          is already enabled
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail)
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_is_enabled

      - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
          preauth editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so preauth
          insertbefore: ^auth.*sufficient.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
          authfail editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so authfail
          insertbefore: ^auth.*required.*pam_deny\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Configure the root Account for Failed Password Attempts - Enable pam_faillock.so
          account section editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: account     required      pam_faillock.so
          insertbefore: ^account.*required.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_authselect_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Check the presence
        of /etc/security/faillock.conf file
      ansible.builtin.stat:
        path: /etc/security/faillock.conf
      register: result_faillock_conf_check
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
        even_deny_root parameter in /etc/security/faillock.conf
      ansible.builtin.lineinfile:
        path: /etc/security/faillock.conf
        regexp: ^\s*even_deny_root
        line: even_deny_root
        state: present
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
        even_deny_root parameter not in PAM files
      block:

      - name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/system-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/system-auth
        register: result_pam_file_present

      - name: Configure the root Account for Failed Password Attempts - Check the proper
          remediation for the system
        block:

        - name: Configure the root Account for Failed Password Attempts - Define the PAM
            file to be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/system-auth

        - name: Configure the root Account for Failed Password Attempts - Check if system
            relies on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Configure the root Account for Failed Password Attempts - Ensure authselect
            custom profile is used if authselect is present
          block:

          - name: Configure the root Account for Failed Password Attempts - Check integrity
              of authselect current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Configure the root Account for Failed Password Attempts - Informative
              message based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Configure the root Account for Failed Password Attempts - Get authselect
              current profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Configure the root Account for Failed Password Attempts - Define the
              current authselect profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Define the
              new authselect custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Get authselect
              current features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Check if any
              custom profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Create an
              authselect custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Configure the root Account for Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Configure the root Account for Failed Password Attempts - Ensure the
              authselect custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Configure the root Account for Failed Password Attempts - Restore the
              authselect features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Configure the root Account for Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Configure the root Account for Failed Password Attempts - Change the
              PAM file to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Configure the root Account for Failed Password Attempts - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists

      - name: Configure the root Account for Failed Password Attempts - Check if /etc/pam.d/password-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/password-auth
        register: result_pam_file_present

      - name: Configure the root Account for Failed Password Attempts - Check the proper
          remediation for the system
        block:

        - name: Configure the root Account for Failed Password Attempts - Define the PAM
            file to be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/password-auth

        - name: Configure the root Account for Failed Password Attempts - Check if system
            relies on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Configure the root Account for Failed Password Attempts - Ensure authselect
            custom profile is used if authselect is present
          block:

          - name: Configure the root Account for Failed Password Attempts - Check integrity
              of authselect current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Configure the root Account for Failed Password Attempts - Informative
              message based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Configure the root Account for Failed Password Attempts - Get authselect
              current profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Configure the root Account for Failed Password Attempts - Define the
              current authselect profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Define the
              new authselect custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Get authselect
              current features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Check if any
              custom profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Configure the root Account for Failed Password Attempts - Create an
              authselect custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Configure the root Account for Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Configure the root Account for Failed Password Attempts - Ensure the
              authselect custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Configure the root Account for Failed Password Attempts - Restore the
              authselect features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Configure the root Account for Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Configure the root Account for Failed Password Attempts - Change the
              PAM file to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Configure the root Account for Failed Password Attempts - Ensure the "even_deny_root"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\beven_deny_root\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Configure the root Account for Failed Password Attempts - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Configure the root Account for Failed Password Attempts - Ensure the pam_faillock.so
        even_deny_root parameter in PAM files
      block:

      - name: Configure the root Account for Failed Password Attempts - Check if pam_faillock.so
          even_deny_root parameter is already enabled in pam files
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail).*even_deny_root
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_even_deny_root_parameter_is_present

      - name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
          of pam_faillock.so preauth even_deny_root parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
          line: \1required\3 even_deny_root
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_even_deny_root_parameter_is_present.found == 0

      - name: Configure the root Account for Failed Password Attempts - Ensure the inclusion
          of pam_faillock.so authfail even_deny_root parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
          line: \1required\3 even_deny_root
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_even_deny_root_parameter_is_present.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010330
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(c)
      - accounts_passwords_pam_faillock_deny_root
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Interval For Counting Failed Password Attempts [ref]

Utilizing `pam_faillock.so`, the `fail_interval` directive configures the system to lock out an account after a number of incorrect login attempts within a specified time period. Ensure that the file `/etc/security/faillock.conf` contains the following entry: `fail_interval = <interval-in-seconds>` where `interval-in-seconds` is `900` or greater. In order to avoid errors when manually editing these files, it is recommended to use the appropriate tools, such as `authselect` or `authconfig`, depending on the OS version.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. If the system supports the `/etc/security/faillock.conf` file, the pam_faillock parameters should be defined in `faillock.conf` file.

Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_interval

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), PR.AC-7, FIA_AFL.1, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010320, SV-221690r880681_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_accounts_passwords_pam_faillock_fail_interval='900'

    if [ -f /usr/bin/authselect ]; then
        if ! authselect check; then
    echo "
    authselect integrity check failed. Remediation aborted!
    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
    It is not recommended to manually edit the PAM files when authselect tool is available.
    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
    exit 1
    fi
    authselect enable-feature with-faillock

    authselect apply-changes -b
    else

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
            sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
            sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
        fi
        sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
    done

    fi

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")

    FAILLOCK_CONF="/etc/security/faillock.conf"
    if [ -f $FAILLOCK_CONF ]; then
        regex="^\s*fail_interval\s*="
        line="fail_interval = $var_accounts_passwords_pam_faillock_fail_interval"
        if ! grep -q $regex $FAILLOCK_CONF; then
            echo $line >> $FAILLOCK_CONF
        else
            sed -i --follow-symlinks 's|^\s*\(fail_interval\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_fail_interval"'|g' $FAILLOCK_CONF
        fi
        for pam_file in "${AUTH_FILES[@]}"
        do
            if [ -e "$pam_file" ] ; then
                PAM_FILE_PATH="$pam_file"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$pam_file")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bfail_interval\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bfail_interval\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$pam_file was not found" >&2
            fi
        done
    else
        for pam_file in "${AUTH_FILES[@]}"
        do
            if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*fail_interval' "$pam_file"; then
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ fail_interval='"$var_accounts_passwords_pam_faillock_fail_interval"'/' "$pam_file"
            else
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"fail_interval"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_fail_interval"'\3/' "$pam_file"
            fi
        done
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
        tool is present
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check integrity of
          authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Interval For Counting Failed Password Attempts - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Interval For Counting Failed Password Attempts - Get authselect current
          features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Interval For Counting Failed Password Attempts - Ensure "with-faillock"
          feature is enabled using authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature with-faillock
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("with-faillock")

      - name: Set Interval For Counting Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Remediation where authselect
        tool is not present
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
          is already enabled
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail)
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_is_enabled

      - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
          preauth editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so preauth
          insertbefore: ^auth.*sufficient.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
          authfail editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so authfail
          insertbefore: ^auth.*required.*pam_deny\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Set Interval For Counting Failed Password Attempts - Enable pam_faillock.so
          account section editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: account     required      pam_faillock.so
          insertbefore: ^account.*required.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_authselect_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_passwords_pam_faillock_fail_interval # promote to variable
      set_fact:
        var_accounts_passwords_pam_faillock_fail_interval: !!str 900
      tags:
        - always

    - name: Set Interval For Counting Failed Password Attempts - Check the presence of
        /etc/security/faillock.conf file
      ansible.builtin.stat:
        path: /etc/security/faillock.conf
      register: result_faillock_conf_check
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
        fail_interval parameter in /etc/security/faillock.conf
      ansible.builtin.lineinfile:
        path: /etc/security/faillock.conf
        regexp: ^\s*fail_interval\s*=
        line: fail_interval = {{ var_accounts_passwords_pam_faillock_fail_interval }}
        state: present
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
        fail_interval parameter not in PAM files
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/system-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/system-auth
        register: result_pam_file_present

      - name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Set Interval For Counting Failed Password Attempts - Define the PAM file
            to be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/system-auth

        - name: Set Interval For Counting Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
            custom profile is used if authselect is present
          block:

          - name: Set Interval For Counting Failed Password Attempts - Check integrity
              of authselect current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Set Interval For Counting Failed Password Attempts - Informative message
              based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Set Interval For Counting Failed Password Attempts - Get authselect
              current profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Set Interval For Counting Failed Password Attempts - Define the current
              authselect profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Define the new
              authselect custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Get authselect
              current features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Check if any custom
              profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Interval For Counting Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Interval For Counting Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Set Interval For Counting Failed Password Attempts - Change the PAM
              file to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists

      - name: Set Interval For Counting Failed Password Attempts - Check if /etc/pam.d/password-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/password-auth
        register: result_pam_file_present

      - name: Set Interval For Counting Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Set Interval For Counting Failed Password Attempts - Define the PAM file
            to be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/password-auth

        - name: Set Interval For Counting Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
            custom profile is used if authselect is present
          block:

          - name: Set Interval For Counting Failed Password Attempts - Check integrity
              of authselect current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Set Interval For Counting Failed Password Attempts - Informative message
              based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Set Interval For Counting Failed Password Attempts - Get authselect
              current profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Set Interval For Counting Failed Password Attempts - Define the current
              authselect profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Define the new
              authselect custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Get authselect
              current features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Check if any custom
              profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Set Interval For Counting Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Interval For Counting Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Interval For Counting Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
              changes are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Set Interval For Counting Failed Password Attempts - Change the PAM
              file to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Set Interval For Counting Failed Password Attempts - Ensure the "fail_interval"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bfail_interval\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Set Interval For Counting Failed Password Attempts - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interval For Counting Failed Password Attempts - Ensure the pam_faillock.so
        fail_interval parameter in PAM files
      block:

      - name: Set Interval For Counting Failed Password Attempts - Check if pam_faillock.so
          fail_interval parameter is already enabled in pam files
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail).*fail_interval
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_fail_interval_parameter_is_present

      - name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
          of pam_faillock.so preauth fail_interval parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
          line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
            }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_fail_interval_parameter_is_present.found == 0

      - name: Set Interval For Counting Failed Password Attempts - Ensure the inclusion
          of pam_faillock.so authfail fail_interval parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
          line: \1required\3 fail_interval={{ var_accounts_passwords_pam_faillock_fail_interval
            }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_fail_interval_parameter_is_present.found == 0

      - name: Set Interval For Counting Failed Password Attempts - Ensure the desired
          value for pam_faillock.so preauth fail_interval parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(fail_interval)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_fail_interval_parameter_is_present.found > 0

      - name: Set Interval For Counting Failed Password Attempts - Ensure the desired
          value for pam_faillock.so authfail fail_interval parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(fail_interval)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_fail_interval }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_fail_interval_parameter_is_present.found > 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_faillock_conf_check.stat.exists
      tags:
      - DISA-STIG-OL07-00-010320
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - accounts_passwords_pam_faillock_interval
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Lockout Time for Failed Password Attempts [ref]

This rule configures the system to lock out accounts during a specified time period after a number of incorrect login attempts using `pam_faillock.so`. Ensure that the file `/etc/security/faillock.conf` contains the following entry: `unlock_time=<interval-in-seconds>` where `interval-in-seconds` is `0` or greater. pam_faillock.so module requires multiple entries in pam files. These entries must be carefully defined to work as expected. In order to avoid any errors when manually editing these files, it is recommended to use the appropriate tools, such as `authselect` or `authconfig`, depending on the OS version. If `unlock_time` is set to `0`, manual intervention by an administrator is required to unlock a user. This should be done using the `faillock` tool.
Warning: If the system supports the new `/etc/security/faillock.conf` file but the pam_faillock.so parameters are defined directly in `/etc/pam.d/system-auth` and `/etc/pam.d/password-auth`, the remediation will migrate the `unlock_time` parameter to `/etc/security/faillock.conf` to ensure compatibility with `authselect` tool. The parameters `deny` and `fail_interval`, if used, also have to be migrated by their respective remediation.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. If the system supports the `/etc/security/faillock.conf` file, the pam_faillock parameters should be defined in `faillock.conf` file.

Rationale: | By limiting the number of failed logon attempts the risk of unauthorized system access via user password guessing, otherwise known as brute-forcing, is reduced. Limits are imposed by locking the account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_passwords_pam_faillock_unlock_time

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5.5.3, DSS05.04, DSS05.10, DSS06.10, 3.1.8, CCI-000044, CCI-002236, CCI-002237, CCI-002238, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(b), PR.AC-7, FIA_AFL.1, Req-8.1.7, 8.3.4, SRG-OS-000329-GPOS-00128, SRG-OS-000021-GPOS-00005, OL07-00-010320, SV-221690r880681_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_accounts_passwords_pam_faillock_unlock_time='0'

    if [ -f /usr/bin/authselect ]; then
        if ! authselect check; then
    echo "
    authselect integrity check failed. Remediation aborted!
    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
    It is not recommended to manually edit the PAM files when authselect tool is available.
    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
    exit 1
    fi
    authselect enable-feature with-faillock

    authselect apply-changes -b
    else

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")
    for pam_file in "${AUTH_FILES[@]}"
    do
        if ! grep -qE '^\s*auth\s+required\s+pam_faillock\.so\s+(preauth silent|authfail).*$' "$pam_file" ; then
            sed -i --follow-symlinks '/^auth.*sufficient.*pam_unix\.so.*/i auth        required      pam_faillock.so preauth silent' "$pam_file"
            sed -i --follow-symlinks '/^auth.*required.*pam_deny\.so.*/i auth        required      pam_faillock.so authfail' "$pam_file"
            sed -i --follow-symlinks '/^account.*required.*pam_unix\.so.*/i account     required      pam_faillock.so' "$pam_file"
        fi
        sed -Ei 's/(auth.*)(\[default=die\])(.*pam_faillock\.so)/\1required     \3/g' "$pam_file"
    done

    fi

    AUTH_FILES=("/etc/pam.d/system-auth" "/etc/pam.d/password-auth")

    FAILLOCK_CONF="/etc/security/faillock.conf"
    if [ -f $FAILLOCK_CONF ]; then
        regex="^\s*unlock_time\s*="
        line="unlock_time = $var_accounts_passwords_pam_faillock_unlock_time"
        if ! grep -q $regex $FAILLOCK_CONF; then
            echo $line >> $FAILLOCK_CONF
        else
            sed -i --follow-symlinks 's|^\s*\(unlock_time\s*=\s*\)\(\S\+\)|\1'"$var_accounts_passwords_pam_faillock_unlock_time"'|g' $FAILLOCK_CONF
        fi
        for pam_file in "${AUTH_FILES[@]}"
        do
            if [ -e "$pam_file" ] ; then
                PAM_FILE_PATH="$pam_file"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$pam_file")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*auth\s.*\bpam_faillock.so\s.*\bunlock_time\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*auth.*pam_faillock.so.*)\bunlock_time\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$pam_file was not found" >&2
            fi
        done
    else
        for pam_file in "${AUTH_FILES[@]}"
        do
            if ! grep -qE '^\s*auth.*pam_faillock\.so (preauth|authfail).*unlock_time' "$pam_file"; then
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*preauth.*silent.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
                sed -i --follow-symlinks '/^auth.*required.*pam_faillock\.so.*authfail.*/ s/$/ unlock_time='"$var_accounts_passwords_pam_faillock_unlock_time"'/' "$pam_file"
            else
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*preauth.*silent.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
                sed -i --follow-symlinks 's/\(^auth.*required.*pam_faillock\.so.*authfail.*\)\('"unlock_time"'=\)[0-9]\+\(.*\)/\1\2'"$var_accounts_passwords_pam_faillock_unlock_time"'\3/' "$pam_file"
            fi
        done
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Check if system relies on
        authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
        tool is present
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Set Lockout Time for Failed Password Attempts - Informative message based
          on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Set Lockout Time for Failed Password Attempts - Get authselect current features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Set Lockout Time for Failed Password Attempts - Ensure "with-faillock" feature
          is enabled using authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature with-faillock
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("with-faillock")

      - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Remediation where authselect
        tool is not present
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
          is already enabled
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail)
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_is_enabled

      - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so preauth
          editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so preauth
          insertbefore: ^auth.*sufficient.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so authfail
          editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: auth        required      pam_faillock.so authfail
          insertbefore: ^auth.*required.*pam_deny\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0

      - name: Set Lockout Time for Failed Password Attempts - Enable pam_faillock.so account
          section editing PAM files
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          line: account     required      pam_faillock.so
          insertbefore: ^account.*required.*pam_unix\.so.*
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_is_enabled.found == 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_passwords_pam_faillock_unlock_time # promote to variable
      set_fact:
        var_accounts_passwords_pam_faillock_unlock_time: !!str 0
      tags:
        - always

    - name: Set Lockout Time for Failed Password Attempts - Check the presence of /etc/security/faillock.conf
        file
      ansible.builtin.stat:
        path: /etc/security/faillock.conf
      register: result_faillock_conf_check
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
        unlock_time parameter in /etc/security/faillock.conf
      ansible.builtin.lineinfile:
        path: /etc/security/faillock.conf
        regexp: ^\s*unlock_time\s*=
        line: unlock_time = {{ var_accounts_passwords_pam_faillock_unlock_time }}
        state: present
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
        unlock_time parameter not in PAM files
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/system-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/system-auth
        register: result_pam_file_present

      - name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
            be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/system-auth

        - name: Set Lockout Time for Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
            profile is used if authselect is present
          block:

          - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
              current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Set Lockout Time for Failed Password Attempts - Informative message
              based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Set Lockout Time for Failed Password Attempts - Get authselect current
              profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Set Lockout Time for Failed Password Attempts - Define the current authselect
              profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Define the new authselect
              custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Get authselect current
              features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Check if any custom
              profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Lockout Time for Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Lockout Time for Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Set Lockout Time for Failed Password Attempts - Change the PAM file
              to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
            are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists

      - name: Set Lockout Time for Failed Password Attempts - Check if /etc/pam.d/password-auth
          file is present
        ansible.builtin.stat:
          path: /etc/pam.d/password-auth
        register: result_pam_file_present

      - name: Set Lockout Time for Failed Password Attempts - Check the proper remediation
          for the system
        block:

        - name: Set Lockout Time for Failed Password Attempts - Define the PAM file to
            be edited as a local fact
          ansible.builtin.set_fact:
            pam_file_path: /etc/pam.d/password-auth

        - name: Set Lockout Time for Failed Password Attempts - Check if system relies
            on authselect tool
          ansible.builtin.stat:
            path: /usr/bin/authselect
          register: result_authselect_present

        - name: Set Lockout Time for Failed Password Attempts - Ensure authselect custom
            profile is used if authselect is present
          block:

          - name: Set Lockout Time for Failed Password Attempts - Check integrity of authselect
              current profile
            ansible.builtin.command:
              cmd: authselect check
            register: result_authselect_check_cmd
            changed_when: false
            failed_when: false

          - name: Set Lockout Time for Failed Password Attempts - Informative message
              based on the authselect integrity check result
            ansible.builtin.assert:
              that:
              - result_authselect_check_cmd.rc == 0
              fail_msg:
              - authselect integrity check failed. Remediation aborted!
              - This remediation could not be applied because an authselect profile was
                not selected or the selected profile is not intact.
              - It is not recommended to manually edit the PAM files when authselect tool
                is available.
              - In cases where the default authselect profile does not cover a specific
                demand, a custom authselect profile is recommended.
              success_msg:
              - authselect integrity check passed

          - name: Set Lockout Time for Failed Password Attempts - Get authselect current
              profile
            ansible.builtin.shell:
              cmd: authselect current -r | awk '{ print $1 }'
            register: result_authselect_profile
            changed_when: false
            when:
            - result_authselect_check_cmd is success

          - name: Set Lockout Time for Failed Password Attempts - Define the current authselect
              profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Define the new authselect
              custom profile as a local fact
            ansible.builtin.set_fact:
              authselect_current_profile: '{{ result_authselect_profile.stdout }}'
              authselect_custom_profile: custom/hardening
            when:
            - result_authselect_profile is not skipped
            - result_authselect_profile.stdout is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Get authselect current
              features to also enable them in the custom profile
            ansible.builtin.shell:
              cmd: authselect current | tail -n+3 | awk '{ print $2 }'
            register: result_authselect_features
            changed_when: false
            when:
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Check if any custom
              profile with the same name was already created
            ansible.builtin.stat:
              path: /etc/authselect/{{ authselect_custom_profile }}
            register: result_authselect_custom_profile_present
            changed_when: false
            when:
            - authselect_current_profile is not match("custom/")

          - name: Set Lockout Time for Failed Password Attempts - Create an authselect
              custom profile based on the current profile
            ansible.builtin.command:
              cmd: authselect create-profile hardening -b {{ authselect_current_profile
                }}
            when:
            - result_authselect_check_cmd is success
            - authselect_current_profile is not match("custom/")
            - not result_authselect_custom_profile_present.stat.exists

          - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Lockout Time for Failed Password Attempts - Ensure the authselect
              custom profile is selected
            ansible.builtin.command:
              cmd: authselect select {{ authselect_custom_profile }}
            register: result_pam_authselect_select_profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - authselect_current_profile is not match("custom/")
            - authselect_custom_profile is not match(authselect_current_profile)

          - name: Set Lockout Time for Failed Password Attempts - Restore the authselect
              features in the custom profile
            ansible.builtin.command:
              cmd: authselect enable-feature {{ item }}
            loop: '{{ result_authselect_features.stdout_lines }}'
            register: result_pam_authselect_restore_features
            when:
            - result_authselect_profile is not skipped
            - result_authselect_features is not skipped
            - result_pam_authselect_select_profile is not skipped

          - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
              are applied
            ansible.builtin.command:
              cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
            when:
            - result_authselect_check_cmd is success
            - result_authselect_profile is not skipped
            - result_pam_authselect_restore_features is not skipped

          - name: Set Lockout Time for Failed Password Attempts - Change the PAM file
              to be edited according to the custom authselect profile
            ansible.builtin.set_fact:
              pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
                | basename }}
          when:
          - result_authselect_present.stat.exists

        - name: Set Lockout Time for Failed Password Attempts - Ensure the "unlock_time"
            option from "pam_faillock.so" is not present in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: (.*auth.*pam_faillock.so.*)\bunlock_time\b=?[0-9a-zA-Z]*(.*)
            replace: \1\2
          register: result_pam_option_removal

        - name: Set Lockout Time for Failed Password Attempts - Ensure authselect changes
            are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present.stat.exists
          - result_pam_option_removal is changed
        when:
        - result_pam_file_present.stat.exists
      when:
      - '"pam" in ansible_facts.packages'
      - result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Lockout Time for Failed Password Attempts - Ensure the pam_faillock.so
        unlock_time parameter in PAM files
      block:

      - name: Set Lockout Time for Failed Password Attempts - Check if pam_faillock.so
          unlock_time parameter is already enabled in pam files
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: .*auth.*pam_faillock\.so (preauth|authfail).*unlock_time
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_faillock_unlock_time_parameter_is_present

      - name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
          pam_faillock.so preauth unlock_time parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)
          line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
            }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_unlock_time_parameter_is_present.found == 0

      - name: Set Lockout Time for Failed Password Attempts - Ensure the inclusion of
          pam_faillock.so authfail unlock_time parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)
          line: \1required\3 unlock_time={{ var_accounts_passwords_pam_faillock_unlock_time
            }}
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_unlock_time_parameter_is_present.found == 0

      - name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
          for pam_faillock.so preauth unlock_time parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so preauth.*)(unlock_time)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_unlock_time_parameter_is_present.found > 0

      - name: Set Lockout Time for Failed Password Attempts - Ensure the desired value
          for pam_faillock.so authfail unlock_time parameter in auth section
        ansible.builtin.lineinfile:
          path: '{{ item }}'
          backrefs: true
          regexp: (^\s*auth\s+)([\w\[].*\b)(\s+pam_faillock.so authfail.*)(unlock_time)=[0-9]+(.*)
          line: \1required\3\4={{ var_accounts_passwords_pam_faillock_unlock_time }}\5
          state: present
        loop:
        - /etc/pam.d/system-auth
        - /etc/pam.d/password-auth
        when:
        - result_pam_faillock_unlock_time_parameter_is_present.found > 0
      when:
      - '"pam" in ansible_facts.packages'
      - not result_faillock_conf_check.stat.exists
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010320
      - NIST-800-171-3.1.8
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-8.1.7
      - PCI-DSSv4-8.3.4
      - accounts_passwords_pam_faillock_unlock_time
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Set Password Quality Requirements Group contains 1 group and 10 rules

[ref] The default `pam_pwquality` PAM module provides strength checking for passwords. It performs a number of checks, such as making sure passwords are not similar to dictionary words, are of at least a certain length, are not the previous password reversed, and are not simply a change of case from the previous password. It can also require passwords to be in certain character classes. The `pam_pwquality` module is the preferred way of configuring password requirements.
The man pages `pam_pwquality(8)` provide information on the capabilities and configuration of each.

Group Set Password Quality Requirements with pam_pwquality Group contains 10 rules

[ref] The `pam_pwquality` PAM module can be configured to meet requirements for a variety of policies.
For example, to configure `pam_pwquality` to require at least one uppercase character, lowercase character, digit, and other (special) character, make sure that `pam_pwquality` exists in `/etc/pam.d/system-auth`:

    password    requisite     pam_pwquality.so try_first_pass local_users_only retry=3 authtok_type=

If no such line exists, add one as the first line of the password section in `/etc/pam.d/system-auth`. Next, modify the settings in `/etc/security/pwquality.conf` to match the following:

    difok = 4
    minlen = 14
    dcredit = -1
    ucredit = -1
    lcredit = -1
    ocredit = -1
    maxrepeat = 3

The arguments can be modified to ensure compliance with your organization's security policy. Discussion of each parameter follows.

#### Rule Ensure PAM Enforces Password Requirements - Minimum Digit Characters [ref]

The pam_pwquality module's `dcredit` parameter controls requirements for usage of digits in a password. When set to a negative number, any password will be required to contain that many digits. When set to a positive number, pam_pwquality will grant +1 additional length credit for each digit. Modify the `dcredit` setting in `/etc/security/pwquality.conf` to require the use of a digit in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_dcredit

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000194, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_SMF_EXT.1, Req-8.2.3, 8.3.6, SRG-OS-000071-GPOS-00039, OL07-00-010140, SV-221671r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_dcredit='-1'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bdcredit\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bdcredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^dcredit")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_dcredit"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^dcredit\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^dcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010140
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_dcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_dcredit # promote to variable
      set_fact:
        var_password_pam_dcredit: !!str -1
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
        if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010140
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_dcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
        the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Define
          the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Check
          if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
          authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters -
            Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
          the "dcredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
          }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bdcredit\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
          authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010140
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_dcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Digit Characters - Ensure
        PAM variable dcredit is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*dcredit
        line: dcredit = {{ var_password_pam_dcredit }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010140
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_dcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Minimum Different Characters [ref]

The pam_pwquality module's `difok` parameter sets the number of characters in a password that must not be present in and old password during a password change. Modify the `difok` setting in `/etc/security/pwquality.conf` to equal 8 to require differing characters when changing passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute–force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Requiring a minimum number of different characters during password changes ensures that newly changed passwords should not resemble previously compromised ones. Note that passwords which are changed on compromised systems will still be compromised, however.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_difok

Identifiers and References

References: 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000195, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(b), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000072-GPOS-00040, OL07-00-010160, SV-221673r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_difok='8'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bdifok\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bdifok\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^difok")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_difok"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^difok\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^difok\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010160
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(b)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_difok
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_difok # promote to variable
      set_fact:
        var_password_pam_difok: !!str 8
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters -
        Check if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010160
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(b)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_difok
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters -
        Check the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
          - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
          - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
          - Ensure authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
            - Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
          - Ensure the "difok" option from "pam_pwquality.so" is not present in {{ pam_file_path
          }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bdifok\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters
          - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010160
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(b)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_difok
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Characters -
        Ensure PAM variable difok is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*difok
        line: difok = {{ var_password_pam_difok }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010160
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(b)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_difok
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters [ref]

The pam_pwquality module's `lcredit` parameter controls requirements for usage of lowercase letters in a password. When set to a negative number, any password will be required to contain that many lowercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each lowercase character. Modify the `lcredit` setting in `/etc/security/pwquality.conf` to require the use of a lowercase character in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possble combinations that need to be tested before the password is compromised. Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_lcredit

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000193, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_SMF_EXT.1, Req-8.2.3, 8.3.6, SRG-OS-000070-GPOS-00038, OL07-00-010130, SV-221670r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_lcredit='-1'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\blcredit\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\blcredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^lcredit")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_lcredit"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^lcredit\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^lcredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010130
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_lcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_lcredit # promote to variable
      set_fact:
        var_password_pam_lcredit: !!str -1
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
        Check if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010130
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_lcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
        Check the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
          - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
          - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
          - Ensure authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
            - Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
          - Ensure the "lcredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
          }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\blcredit\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters
          - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010130
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_lcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Lowercase Characters -
        Ensure PAM variable lcredit is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*lcredit
        line: lcredit = {{ var_password_pam_lcredit }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010130
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_lcredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating Characters from Same Character Class [ref]

The pam_pwquality module's `maxclassrepeat` parameter controls requirements for consecutive repeating characters from the same character class. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters from the same character class. Modify the `maxclassrepeat` setting in `/etc/security/pwquality.conf` to equal 4 to prevent a run of (4 + 1) or more identical characters.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex a password, the greater the number of possible combinations that need to be tested before the password is compromised.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_maxclassrepeat

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000195, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000072-GPOS-00040, OL07-00-010190, SV-221676r809140_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_maxclassrepeat='4'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bmaxclassrepeat\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bmaxclassrepeat\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^maxclassrepeat")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_maxclassrepeat"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^maxclassrepeat\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^maxclassrepeat\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010190
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxclassrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_maxclassrepeat # promote to variable
      set_fact:
        var_password_pam_maxclassrepeat: !!str 4
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
        Characters from Same Character Class - Check if /etc/pam.d/system-auth file is
        present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010190
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxclassrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
        Characters from Same Character Class - Check the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
          Characters from Same Character Class - Define the PAM file to be edited as a
          local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
          Characters from Same Character Class - Check if system relies on authselect
          tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
          Characters from Same Character Class - Ensure authselect custom profile is used
          if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Check integrity of authselect current
            profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Informative message based on the authselect
            integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Define the current authselect profile
            as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Define the new authselect custom profile
            as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Get authselect current features to
            also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Check if any custom profile with the
            same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Create an authselect custom profile
            based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Ensure the authselect custom profile
            is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Restore the authselect features in
            the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
            Characters from Same Character Class - Change the PAM file to be edited according
            to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
          Characters from Same Character Class - Ensure the "maxclassrepeat" option from
          "pam_pwquality.so" is not present in {{ pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bmaxclassrepeat\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
          Characters from Same Character Class - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010190
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxclassrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Maximum Consecutive Repeating
        Characters from Same Character Class - Ensure PAM variable maxclassrepeat is set
        accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*maxclassrepeat
        line: maxclassrepeat = {{ var_password_pam_maxclassrepeat }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010190
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxclassrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Password Maximum Consecutive Repeating Characters [ref]

The pam_pwquality module's `maxrepeat` parameter controls requirements for consecutive repeating characters. When set to a positive number, it will reject passwords which contain more than that number of consecutive characters. Modify the `maxrepeat` setting in `/etc/security/pwquality.conf` to equal 3 to prevent a run of (3 + 1) or more identical characters.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_maxrepeat

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000195, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000072-GPOS-00040, OL07-00-010180, SV-221675r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_maxrepeat='3'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bmaxrepeat\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bmaxrepeat\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^maxrepeat")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_maxrepeat"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^maxrepeat\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^maxrepeat\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010180
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_maxrepeat # promote to variable
      set_fact:
        var_password_pam_maxrepeat: !!str 3
      tags:
        - always

    - name: Set Password Maximum Consecutive Repeating Characters - Check if /etc/pam.d/system-auth
        file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010180
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Password Maximum Consecutive Repeating Characters - Check the proper remediation
        for the system
      block:

      - name: Set Password Maximum Consecutive Repeating Characters - Define the PAM file
          to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Set Password Maximum Consecutive Repeating Characters - Check if system
          relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Set Password Maximum Consecutive Repeating Characters - Ensure authselect
          custom profile is used if authselect is present
        block:

        - name: Set Password Maximum Consecutive Repeating Characters - Check integrity
            of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Set Password Maximum Consecutive Repeating Characters - Informative message
            based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Set Password Maximum Consecutive Repeating Characters - Get authselect
            current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Set Password Maximum Consecutive Repeating Characters - Define the current
            authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Set Password Maximum Consecutive Repeating Characters - Define the new
            authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Set Password Maximum Consecutive Repeating Characters - Get authselect
            current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Set Password Maximum Consecutive Repeating Characters - Check if any custom
            profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Set Password Maximum Consecutive Repeating Characters - Create an authselect
            custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Set Password Maximum Consecutive Repeating Characters - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Set Password Maximum Consecutive Repeating Characters - Ensure the authselect
            custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Set Password Maximum Consecutive Repeating Characters - Restore the authselect
            features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Set Password Maximum Consecutive Repeating Characters - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Set Password Maximum Consecutive Repeating Characters - Change the PAM
            file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Set Password Maximum Consecutive Repeating Characters - Ensure the "maxrepeat"
          option from "pam_pwquality.so" is not present in {{ pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bmaxrepeat\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Set Password Maximum Consecutive Repeating Characters - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010180
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Password Maximum Consecutive Repeating Characters - Ensure PAM variable
        maxrepeat is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*maxrepeat
        line: maxrepeat = {{ var_password_pam_maxrepeat }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010180
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_maxrepeat
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Minimum Different Categories [ref]

The pam_pwquality module's `minclass` parameter controls requirements for usage of different character classes, or types, of character that must exist in a password before it is considered valid. For example, setting this value to three (3) requires that any password must have characters from at least three different categories in order to be approved. The default value is zero (0), meaning there are no required classes. There are four categories available:

    * Upper-case characters
    * Lower-case characters
    * Digits
    * Special characters (for example, punctuation)

Modify the `minclass` setting in `/etc/security/pwquality.conf` entry to require 4 differing categories of characters when changing passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Requiring a minimum number of character categories makes password guessing attacks more difficult by ensuring a larger search space.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_minclass

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000195, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000072-GPOS-00040, OL07-00-010170, SV-221674r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_minclass='4'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bminclass\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bminclass\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minclass")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minclass"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^minclass\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^minclass\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010170
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_minclass
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_minclass # promote to variable
      set_fact:
        var_password_pam_minclass: !!str 4
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories -
        Check if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010170
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_minclass
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories -
        Check the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
          - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
          - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
          - Ensure authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
            - Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
          - Ensure the "minclass" option from "pam_pwquality.so" is not present in {{
          pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bminclass\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories
          - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010170
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_minclass
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Different Categories -
        Ensure PAM variable minclass is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*minclass
        line: minclass = {{ var_password_pam_minclass }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010170
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_minclass
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Minimum Length [ref]

The pam_pwquality module's `minlen` parameter controls requirements for minimum characters required in a password. Add `minlen=15` after pam_pwquality to set minimum password length requirements.

Rationale:

The shorter the password, the lower the number of possible combinations that need to be tested before the password is compromised.
Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks. Password length is one factor of several that helps to determine strength and how long it takes to crack a password. Use of more characters in a password helps to exponentially increase the time and/or resources required to compromise the password.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_minlen

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000205, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_SMF_EXT.1, Req-8.2.3, 8.3.6, SRG-OS-000078-GPOS-00046, OL07-00-010280, SV-221686r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_minlen='15'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bminlen\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bminlen\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^minlen")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_minlen"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^minlen\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^minlen\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010280
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_minlen
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_minlen # promote to variable
      set_fact:
        var_password_pam_minlen: !!str 15
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Length - Check if /etc/pam.d/system-auth
        file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010280
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_minlen
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Length - Check the proper
        remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Length - Define the
          PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Length - Check if system
          relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
          custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Check integrity
            of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Informative
            message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Get authselect
            current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Define the
            current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Define the
            new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Get authselect
            current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Check if
            any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Create an
            authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure the
            authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Restore the
            authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Length - Change the
            PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure the
          "minlen" option from "pam_pwquality.so" is not present in {{ pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bminlen\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure authselect
          changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010280
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_minlen
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Length - Ensure PAM variable
        minlen is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*minlen
        line: minlen = {{ var_password_pam_minlen }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010280
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.6
      - accounts_password_pam_minlen
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Minimum Special Characters [ref]

The pam_pwquality module's `ocredit=` parameter controls requirements for usage of special (or "other") characters in a password. When set to a negative number, any password will be required to contain that many special characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each special character. Modify the `ocredit` setting in `/etc/security/pwquality.conf` to equal -1 to require use of a special character in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised. Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_ocredit

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-001619, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_SMF_EXT.1, SRG-OS-000266-GPOS-00101, OL07-00-010150, SV-221672r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_ocredit='-1'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bocredit\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bocredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ocredit")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ocredit"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^ocredit\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^ocredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010150
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_ocredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_ocredit # promote to variable
      set_fact:
        var_password_pam_ocredit: !!str -1
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Check
        if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010150
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_ocredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Check
        the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
          Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
          Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
          Ensure authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters
            - Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
          Ensure the "ocredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
          }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bocredit\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters -
          Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010150
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_ocredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Special Characters - Ensure
        PAM variable ocredit is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*ocredit
        line: ocredit = {{ var_password_pam_ocredit }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010150
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - accounts_password_pam_ocredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted Per-Session [ref]

To configure the number of retry prompts that are permitted per-session: Edit the `pam_pwquality.so` statement in `/etc/pam.d/system-auth` to show `retry=3`, or a lower value if site policy is more restrictive. The DoD requirement is a maximum of 3 prompts per session.
Rationale: | Setting the password retry prompts that are permitted on a per-session basis to a low value requires some software, such as SSH, to re-connect. This can slow down and draw additional attention to some types of password-guessing attacks. Note that this is different from account lockout, which is provided by the pam_faillock module.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_retry

Identifiers and References

References: 1, 11, 12, 15, 16, 3, 5, 9, 5.5.3, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000192, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), AC-7(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, PR.IP-1, FMT_MOF_EXT.1, SRG-OS-000069-GPOS-00037, SRG-OS-000480-GPOS-00227, OL07-00-010119, SV-221668r902779_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_retry='3'

    		if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi
        if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwquality.so\s*.*' "$PAM_FILE_PATH"; then
                # Line matching group + control + module was not found. Check group + module.
                if [ "$(grep -cP '^\s*password\s+.*\s+pam_pwquality.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                    # The control is updated only if one single line matches.
                    sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_pwquality.so.*)/\1'"requisite"' \2/' "$PAM_FILE_PATH"
                else
                    LAST_MATCH_LINE=$(grep -nP "^\s*account" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                    if [ ! -z $LAST_MATCH_LINE ]; then
                        sed -i --follow-symlinks $LAST_MATCH_LINE' a password     '"requisite"'    pam_pwquality.so' "$PAM_FILE_PATH"
                    else
                        echo 'password    '"requisite"'    pam_pwquality.so' >> "$PAM_FILE_PATH"
                    fi
                fi
            fi
            # Check the option
            if ! grep -qP '^\s*password\s+'"requisite"'\s+pam_pwquality.so\s*.*\sretry\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks '/\s*password\s+'"requisite"'\s+pam_pwquality.so.*/ s/$/ retry='"$var_password_pam_retry"'/' "$PAM_FILE_PATH"
            else
                sed -i -E --follow-symlinks 's/(\s*password\s+'"requisite"'\s+pam_pwquality.so\s+.*)('"retry"'=)[[:alnum:]]+\s*(.*)/\1\2'"$var_password_pam_retry"' \3/' "$PAM_FILE_PATH"
            fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
    - name: XCCDF Value var_password_pam_retry # promote to variable
      set_fact:
        var_password_pam_retry: !!str 3
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
        Per-Session - Check if expected PAM module line is present in /etc/pam.d/system-auth
      ansible.builtin.lineinfile:
        path: /etc/pam.d/system-auth
        regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwquality.so\s*.*
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_line_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
        Per-Session - Include or update the PAM module line in /etc/pam.d/system-auth
      block:

      - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
          Permitted Per-Session - Check if required PAM module line is present in /etc/pam.d/system-auth
          with different control
        ansible.builtin.lineinfile:
          path: /etc/pam.d/system-auth
          regexp: ^\s*password\s+.*\s+pam_pwquality.so\s*
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_line_other_control_present

      - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
          Permitted Per-Session - Ensure the correct control for the required PAM module
          line in /etc/pam.d/system-auth
        ansible.builtin.replace:
          dest: /etc/pam.d/system-auth
          regexp: ^(\s*password\s+).*(\bpam_pwquality.so.*)
          replace: \1requisite \2
        register: result_pam_module_edit
        when:
        - result_pam_line_other_control_present.found == 1

      - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
          Permitted Per-Session - Ensure the required PAM module line is included in /etc/pam.d/system-auth
        ansible.builtin.lineinfile:
          dest: /etc/pam.d/system-auth
          insertafter: ^\s*account
          line: password    requisite    pam_pwquality.so
        register: result_pam_module_add
        when:
        - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
          > 1

      - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts
          Permitted Per-Session - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present is defined
        - result_authselect_present.stat.exists
        - |-
          (result_pam_module_add is defined and result_pam_module_add.changed)
           or (result_pam_module_edit is defined and result_pam_module_edit.changed)
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_line_present.found is defined
      - result_pam_line_present.found == 0
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
        Per-Session - Check if the required PAM module option is present in /etc/pam.d/system-auth
      ansible.builtin.lineinfile:
        path: /etc/pam.d/system-auth
        regexp: ^\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwquality.so\s*.*\sretry\b
        state: absent
      check_mode: true
      changed_when: false
      register: result_pam_module_retry_option_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
        Per-Session - Ensure the "retry" PAM option for "pam_pwquality.so" is included
        in /etc/pam.d/system-auth
      ansible.builtin.lineinfile:
        path: /etc/pam.d/system-auth
        backrefs: true
        regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwquality.so.*)
        line: \1 retry={{ var_password_pam_retry }}
        state: present
      register: result_pam_retry_add
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_module_retry_option_present.found == 0
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure PAM Enforces Password Requirements - Authentication Retry Prompts Permitted
        Per-Session - Ensure the required value for "retry" PAM option from "pam_pwquality.so"
        in /etc/pam.d/system-auth
      ansible.builtin.lineinfile:
        path: /etc/pam.d/system-auth
        backrefs: true
        regexp: ^(\s*password\s+{{ 'requisite' | regex_escape() }}\s+pam_pwquality.so\s+.*)(retry)=[0-9a-zA-Z]+\s*(.*)
        line: \1\2={{ var_password_pam_retry }} \3
      register: result_pam_retry_edit
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_module_retry_option_present.found > 0
      tags:
      - CJIS-5.5.3
      - DISA-STIG-OL07-00-010119
      - NIST-800-53-AC-7(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(4)
      - accounts_password_pam_retry
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters [ref]

The pam_pwquality module's `ucredit=` parameter controls requirements for usage of uppercase letters in a password. When set to a negative number, any password will be required to contain that many uppercase characters. When set to a positive number, pam_pwquality will grant +1 additional length credit for each uppercase character. Modify the `ucredit` setting in `/etc/security/pwquality.conf` to require the use of an uppercase character in passwords.

Rationale:

Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_pam_ucredit

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000192, CCI-000193, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(a), CM-6(a), IA-5(4), PR.AC-1, PR.AC-6, PR.AC-7, FMT_SMF_EXT.1, Req-8.2.3, SRG-OS-000069-GPOS-00037, SRG-OS-000070-GPOS-00038, OL07-00-010120, SV-221669r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_password_pam_ucredit='-1'

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi

    if grep -qP '^\s*password\s.*\bpam_pwquality.so\s.*\bucredit\b' "$PAM_FILE_PATH"; then
        sed -i -E --follow-symlinks 's/(.*password.*pam_pwquality.so.*)\bucredit\b=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
    fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ucredit")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_password_pam_ucredit"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^ucredit\\>" "/etc/security/pwquality.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^ucredit\\>.*/$escaped_formatted_output/gi" "/etc/security/pwquality.conf"
    else
        if [[ -s "/etc/security/pwquality.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/security/pwquality.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/security/pwquality.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/security/pwquality.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010120
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - accounts_password_pam_ucredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_password_pam_ucredit # promote to variable
      set_fact:
        var_password_pam_ucredit: !!str -1
      tags:
        - always

    - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
        Check if /etc/pam.d/system-auth file is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010120
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - accounts_password_pam_ucredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
        Check the proper remediation for the system
      block:

      - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
          - Define the PAM file to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
          - Check if system relies on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
          - Ensure authselect custom profile is used if authselect is present
        block:

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Check integrity of authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Informative message based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Define the current authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Define the new authselect custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Get authselect current features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Check if any custom profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Create an authselect custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Ensure the authselect custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Restore the authselect features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
            - Change the PAM file to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
          - Ensure the "ucredit" option from "pam_pwquality.so" is not present in {{ pam_file_path
          }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*password.*pam_pwquality.so.*)\bucredit\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal

      - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters
          - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - result_pam_option_removal is changed
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - DISA-STIG-OL07-00-010120
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - accounts_password_pam_ucredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure PAM Enforces Password Requirements - Minimum Uppercase Characters -
        Ensure PAM variable ucredit is set accordingly
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/security/pwquality.conf
        regexp: ^#?\s*ucredit
        line: ucredit = {{ var_password_pam_ucredit }}
      when: '"pam" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010120
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(4)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - accounts_password_pam_ucredit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Set Password Hashing Algorithm Group contains 3 rules
[ref] The system's default algorithm for storing password hashes in `/etc/shadow` is SHA-512. This can be configured in several locations.

#### Rule Set Password Hashing Algorithm in /etc/libuser.conf [ref]

In `/etc/libuser.conf`, add or correct the following line in its `[defaults]` section to ensure the system will use the SHA-512 algorithm for password hashing:

    crypt_style = sha512

Rationale:

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kepy in plain text.
This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the `crypt_style` configuration option ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_libuserconf

Identifiers and References

References: 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, OL07-00-010220, SV-221680r877397_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q libuser; then

    LIBUSER_CONF="/etc/libuser.conf"
    CRYPT_STYLE_REGEX='[[:space:]]*\[defaults](.*(\n)+)+?[[:space:]]*crypt_style[[:space:]]*'

    # Try find crypt_style in [defaults] section. If it is here, then change algorithm to sha512.
    # If it isn't here, then add it to [defaults] section.
    if grep -qzosP $CRYPT_STYLE_REGEX $LIBUSER_CONF ; then
            sed -i "s/\(crypt_style[[:space:]]*=[[:space:]]*\).*/\1sha512/g" $LIBUSER_CONF
    elif grep -qs "\[defaults]" $LIBUSER_CONF ; then
            sed -i "/[[:space:]]*\[defaults]/a crypt_style = sha512" $LIBUSER_CONF
    else
            echo -e "[defaults]\ncrypt_style = sha512" >> $LIBUSER_CONF
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010220
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - set_password_hashing_algorithm_libuserconf

    - name: Set Password Hashing Algorithm in /etc/libuser.conf
      lineinfile:
        dest: /etc/libuser.conf
        insertafter: ^\s*\[defaults]
        regexp: ^#?crypt_style
        line: crypt_style = sha512
        state: present
        create: true
      when: '"libuser" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010220
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - set_password_hashing_algorithm_libuserconf

#### Rule Set Password Hashing Algorithm in /etc/login.defs [ref]

In `/etc/login.defs`, add or correct the following line to ensure the system will use SHA512 as the hashing algorithm:

    ENCRYPT_METHOD SHA512

Rationale:

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kept in plain text.
Using a stronger hashing algorithm makes password cracking attacks more difficult.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_logindefs

Identifiers and References

References: BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, OL07-00-010210, SV-221678r877397_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_password_hashing_algorithm='SHA512'

    if grep --silent ^ENCRYPT_METHOD /etc/login.defs ; then
    	sed -i "s/^ENCRYPT_METHOD .*/ENCRYPT_METHOD $var_password_hashing_algorithm/g" /etc/login.defs
    else
    	echo "" >> /etc/login.defs
    	echo "ENCRYPT_METHOD $var_password_hashing_algorithm" >> /etc/login.defs
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010210
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - set_password_hashing_algorithm_logindefs
    - name: XCCDF Value var_password_hashing_algorithm # promote to variable
      set_fact:
        var_password_hashing_algorithm: !!str SHA512
      tags:
        - always

    - name: Set Password Hashing Algorithm in /etc/login.defs
      lineinfile:
        dest: /etc/login.defs
        regexp: ^#?ENCRYPT_METHOD
        line: ENCRYPT_METHOD {{ var_password_hashing_algorithm }}
        state: present
        create: true
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010210
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - set_password_hashing_algorithm_logindefs

#### Rule Set PAM''s Password Hashing Algorithm [ref]

The PAM system service can be configured to only store encrypted representations of passwords. In "/etc/pam.d/system-auth", the `password` section of the file controls which PAM modules execute during a password change. Set the `pam_unix.so` module in the `password` section to include the argument `sha512`, as shown below:

    password    sufficient    pam_unix.so sha512 other arguments...

This will help ensure when local users change their passwords, hashes for the new passwords will be generated using the SHA-512 algorithm. This is the default.

Rationale:

Passwords need to be protected at all times, and encryption is the standard method for protecting passwords. If passwords are not encrypted, they can be plainly read (i.e., clear text) and easily compromised. Passwords that are encrypted with a weak algorithm are no more protected than if they are kepy in plain text.
This setting ensures user and group account administration utilities are configured to store only encrypted representations of passwords. Additionally, the `crypt_style` configuration option ensures the use of a strong hashing algorithm that makes password cracking attacks more difficult.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_set_password_hashing_algorithm_systemauth

Identifiers and References

References: BP28(R32), 1, 12, 15, 16, 5, 5.6.2.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.13.11, CCI-000196, CCI-000803, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(c), IA-5(1)(c), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2, SRG-OS-000073-GPOS-00041, SRG-OS-000120-GPOS-00061, OL07-00-010200, SV-221677r917840_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    if [ -e "/etc/pam.d/system-auth" ] ; then
        PAM_FILE_PATH="/etc/pam.d/system-auth"
        if [ -f /usr/bin/authselect ]; then

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/system-auth")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
        fi
        if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*' "$PAM_FILE_PATH"; then
                # Line matching group + control + module was not found. Check group + module.
                if [ "$(grep -cP '^\s*password\s+.*\s+pam_unix.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                    # The control is updated only if one single line matches.
                    sed -i -E --follow-symlinks 's/^(\s*password\s+).*(\bpam_unix.so.*)/\1'"sufficient"' \2/' "$PAM_FILE_PATH"
                else
                    echo 'password    '"sufficient"'    pam_unix.so' >> "$PAM_FILE_PATH"
                fi
            fi
            # Check the option
            if ! grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s*.*\ssha512\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks '/\s*password\s+'"sufficient"'\s+pam_unix.so.*/ s/$/ sha512/' "$PAM_FILE_PATH"
            fi
        if [ -f /usr/bin/authselect ]; then

            authselect apply-changes -b
        fi
    else
        echo "/etc/pam.d/system-auth was not found" >&2
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010200
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - set_password_hashing_algorithm_systemauth

    - name: Set PAM's Password Hashing Algorithm - Check if /etc/pam.d/system-auth file
        is present
      ansible.builtin.stat:
        path: /etc/pam.d/system-auth
      register: result_pam_file_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010200
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - set_password_hashing_algorithm_systemauth

    - name: Set PAM's Password Hashing Algorithm - Check the proper remediation for the
        system
      block:

      - name: Set PAM's Password Hashing Algorithm - Define the PAM file to be edited
          as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/system-auth

      - name: Set PAM's Password Hashing Algorithm - Check if system relies on authselect
          tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Set PAM's Password Hashing Algorithm - Ensure authselect custom profile
          is used if authselect is present
        block:

        - name: Set PAM's Password Hashing Algorithm - Check integrity of authselect current
            profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Set PAM's Password Hashing Algorithm - Informative message based on the
            authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Set PAM's Password Hashing Algorithm - Get authselect current profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Set PAM's Password Hashing Algorithm - Define the current authselect profile
            as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Set PAM's Password Hashing Algorithm - Define the new authselect custom
            profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Set PAM's Password Hashing Algorithm - Get authselect current features
            to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Set PAM's Password Hashing Algorithm - Check if any custom profile with
            the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Set PAM's Password Hashing Algorithm - Create an authselect custom profile
            based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Set PAM's Password Hashing Algorithm - Ensure the authselect custom profile
            is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Set PAM's Password Hashing Algorithm - Restore the authselect features
            in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Set PAM's Password Hashing Algorithm - Change the PAM file to be edited
            according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Set PAM's Password Hashing Algorithm - Check if expected PAM module line
          is present in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*password\s+{{ 'sufficient' | regex_escape() }}\s+pam_unix.so\s*.*
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_line_present

      - name: Set PAM's Password Hashing Algorithm - Include or update the PAM module
          line in {{ pam_file_path }}
        block:

        - name: Set PAM's Password Hashing Algorithm - Check if required PAM module line
            is present in {{ pam_file_path }} with different control
          ansible.builtin.lineinfile:
            path: '{{ pam_file_path }}'
            regexp: ^\s*password\s+.*\s+pam_unix.so\s*
            state: absent
          check_mode: true
          changed_when: false
          register: result_pam_line_other_control_present

        - name: Set PAM's Password Hashing Algorithm - Ensure the correct control for
            the required PAM module line in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: ^(\s*password\s+).*(\bpam_unix.so.*)
            replace: \1sufficient \2
          register: result_pam_module_edit
          when:
          - result_pam_line_other_control_present.found == 1

        - name: Set PAM's Password Hashing Algorithm - Ensure the required PAM module
            line is included in {{ pam_file_path }}
          ansible.builtin.lineinfile:
            dest: '{{ pam_file_path }}'
            line: password    sufficient    pam_unix.so
          register: result_pam_module_add
          when:
          - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
            > 1

        - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present is defined
          - result_authselect_present.stat.exists
          - |-
            (result_pam_module_add is defined and result_pam_module_add.changed)
             or (result_pam_module_edit is defined and result_pam_module_edit.changed)
        when:
        - result_pam_line_present.found is defined
        - result_pam_line_present.found == 0

      - name: Set PAM's Password Hashing Algorithm - Check if the required PAM module
          option is present in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*password\s+{{ 'sufficient' | regex_escape() }}\s+pam_unix.so\s*.*\ssha512\b
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_module_sha512_option_present

      - name: Set PAM's Password Hashing Algorithm - Ensure the "sha512" PAM option for
          "pam_unix.so" is included in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          backrefs: true
          regexp: ^(\s*password\s+{{ 'sufficient' | regex_escape() }}\s+pam_unix.so.*)
          line: \1 sha512
          state: present
        register: result_pam_sha512_add
        when:
        - result_pam_module_sha512_option_present.found == 0

      - name: Set PAM's Password Hashing Algorithm - Ensure authselect changes are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_present.stat.exists
        - |-
          (result_pam_sha512_add is defined and result_pam_sha512_add.changed)
           or (result_pam_sha512_edit is defined and result_pam_sha512_edit.changed)
      when:
      - '"pam" in ansible_facts.packages'
      - result_pam_file_present.stat.exists
      tags:
      - CJIS-5.6.2.2
      - DISA-STIG-OL07-00-010200
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.1
      - PCI-DSSv4-8.3.2
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - set_password_hashing_algorithm_systemauth

#### Rule Ensure PAM Displays Last Logon/Access Notification [ref]

To configure the system to notify users of last logon/access using `pam_lastlog`, add or correct the `pam_lastlog` settings in `/etc/pam.d/postlogin` to include `showfailed` option, such as:

    session     required    pam_lastlog.so showfailed

And make sure that the `silent` option is not set for this specific line.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report.
Warning: `authselect` contains an authselect feature to easily and properly enable Last Logon notifications with `pam_lastlog.so` module. If a custom profile was created and used in the system before this authselect feature was available, the new feature can't be used with this custom profile and the remediation will fail. In this case, the custom profile should be recreated or manually updated.

Rationale: | Users need to be aware of activity that occurs regarding their account. Providing users with information regarding the number of unsuccessful attempts that were made to login to their account allows the user to determine if any unauthorized activity has occurred and gives them an opportunity to notify administrators.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_display_login_attempts

Identifiers and References

References: 1, 12, 15, 16, 5.5.2, DSS05.04, DSS05.10, DSS06.10, CCI-000052, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, 0582, 0584, 05885, 0586, 0846, 0957, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-9, AC-9(1), PR.AC-7, Req-10.2.4, 10.2.1.4, SRG-OS-000480-GPOS-00227, OL07-00-040530, SV-221869r858452_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    if [ -f /usr/bin/authselect ]; then
        if authselect list-features minimal | grep -q with-silent-lastlog; then
            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi
            authselect disable-feature with-silent-lastlog

            authselect apply-changes -b
        else

            if ! authselect check; then
            echo "
            authselect integrity check failed. Remediation aborted!
            This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
            It is not recommended to manually edit the PAM files when authselect tool is available.
            In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
            exit 1
            fi

            CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
            # If not already in use, a custom profile is created preserving the enabled features.
            if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                authselect create-profile hardening -b $CURRENT_PROFILE
                CURRENT_PROFILE="custom/hardening"

                authselect apply-changes -b --backup=before-hardening-custom-profile
                authselect select $CURRENT_PROFILE
                for feature in $ENABLED_FEATURES; do
                    authselect enable-feature $feature;
                done

                authselect apply-changes -b --backup=after-hardening-custom-profile
            fi
            PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
            PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

            authselect apply-changes -b
            if [ -e "$PAM_FILE_PATH" ] ; then
                PAM_FILE_PATH="$PAM_FILE_PATH"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi
                if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
                        # Line matching group + control + module was not found. Check group + module.
                        if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                            # The control is updated only if one single line matches.
                            sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"required"' \2/' "$PAM_FILE_PATH"
                        else
                            LAST_MATCH_LINE=$(grep -nP "^\s*session\s+.*pam_succeed_if\.so.*" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                            if [ ! -z $LAST_MATCH_LINE ]; then
                                sed -i --follow-symlinks $LAST_MATCH_LINE' a session     '"required"'    pam_lastlog.so' "$PAM_FILE_PATH"
                            else
                                echo 'session    '"required"'    pam_lastlog.so' >> "$PAM_FILE_PATH"
                            fi
                        fi
                    fi
                    # Check the option
                    if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
                        sed -i -E --follow-symlinks '/\s*session\s+'"required"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
                    fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$PAM_FILE_PATH was not found" >&2
            fi
            if [ -e "$PAM_FILE_PATH" ] ; then
                PAM_FILE_PATH="$PAM_FILE_PATH"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "$PAM_FILE_PATH")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*session.*'"required"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "$PAM_FILE_PATH was not found" >&2
            fi
        fi
    else
        if [ -e "/etc/pam.d/postlogin" ] ; then
                PAM_FILE_PATH="/etc/pam.d/postlogin"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi
                if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*' "$PAM_FILE_PATH"; then
                        # Line matching group + control + module was not found. Check group + module.
                        if [ "$(grep -cP '^\s*session\s+.*\s+pam_lastlog.so\s*' "$PAM_FILE_PATH")" -eq 1 ]; then
                            # The control is updated only if one single line matches.
                            sed -i -E --follow-symlinks 's/^(\s*session\s+).*(\bpam_lastlog.so.*)/\1'"required"' \2/' "$PAM_FILE_PATH"
                        else
                            LAST_MATCH_LINE=$(grep -nP "^\s*session\s+.*pam_succeed_if\.so.*" "$PAM_FILE_PATH" | tail -n 1 | cut -d: -f 1)
                            if [ ! -z $LAST_MATCH_LINE ]; then
                                sed -i --follow-symlinks $LAST_MATCH_LINE' a session     '"required"'    pam_lastlog.so' "$PAM_FILE_PATH"
                            else
                                echo 'session    '"required"'    pam_lastlog.so' >> "$PAM_FILE_PATH"
                            fi
                        fi
                    fi
                    # Check the option
                    if ! grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s*.*\sshowfailed\b' "$PAM_FILE_PATH"; then
                        sed -i -E --follow-symlinks '/\s*session\s+'"required"'\s+pam_lastlog.so.*/ s/$/ showfailed/' "$PAM_FILE_PATH"
                    fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "/etc/pam.d/postlogin was not found" >&2
            fi
        if [ -e "/etc/pam.d/postlogin" ] ; then
                PAM_FILE_PATH="/etc/pam.d/postlogin"
                if [ -f /usr/bin/authselect ]; then

                    if ! authselect check; then
                    echo "
                    authselect integrity check failed. Remediation aborted!
                    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
                    It is not recommended to manually edit the PAM files when authselect tool is available.
                    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
                    exit 1
                    fi

                    CURRENT_PROFILE=$(authselect current -r | awk '{ print $1 }')
                    # If not already in use, a custom profile is created preserving the enabled features.
                    if [[ ! $CURRENT_PROFILE == custom/* ]]; then
                        ENABLED_FEATURES=$(authselect current | tail -n+3 | awk '{ print $2 }')
                        authselect create-profile hardening -b $CURRENT_PROFILE
                        CURRENT_PROFILE="custom/hardening"

                        authselect apply-changes -b --backup=before-hardening-custom-profile
                        authselect select $CURRENT_PROFILE
                        for feature in $ENABLED_FEATURES; do
                            authselect enable-feature $feature;
                        done

                        authselect apply-changes -b --backup=after-hardening-custom-profile
                    fi
                    PAM_FILE_NAME=$(basename "/etc/pam.d/postlogin")
                    PAM_FILE_PATH="/etc/authselect/$CURRENT_PROFILE/$PAM_FILE_NAME"

                    authselect apply-changes -b
                fi

            if grep -qP '^\s*session\s+'"required"'\s+pam_lastlog.so\s.*\bsilent\b' "$PAM_FILE_PATH"; then
                sed -i -E --follow-symlinks 's/(.*session.*'"required"'.*pam_lastlog.so.*)\ssilent=?[[:alnum:]]*(.*)/\1\2/g' "$PAM_FILE_PATH"
            fi
                if [ -f /usr/bin/authselect ]; then

                    authselect apply-changes -b
                fi
            else
                echo "/etc/pam.d/postlogin was not found" >&2
            fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-040530
      - NIST-800-53-AC-9
      - NIST-800-53-AC-9(1)
      - PCI-DSS-Req-10.2.4
      - PCI-DSSv4-10.2.1.4
      - configure_strategy
      - display_login_attempts
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed

    - name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
        on authselect tool
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-040530
      - NIST-800-53-AC-9
      - NIST-800-53-AC-9(1)
      - PCI-DSS-Req-10.2.4
      - PCI-DSSv4-10.2.1.4
      - configure_strategy
      - display_login_attempts
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed

    - name: Ensure PAM Displays Last Logon/Access Notification - Collect the Available
        authselect Features
      ansible.builtin.command:
        cmd: authselect list-features minimal
      register: result_authselect_available_features
      changed_when: false
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-040530
      - NIST-800-53-AC-9
      - NIST-800-53-AC-9(1)
      - PCI-DSS-Req-10.2.4
      - PCI-DSSv4-10.2.1.4
      - configure_strategy
      - display_login_attempts
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed

    - name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
        Using authselect Feature
      block:

      - name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
          authselect current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Ensure PAM Displays Last Logon/Access Notification - Informative message
          based on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect Features
          Currently Enabled
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Ensure PAM Displays Last Logon/Access Notification - Ensure "with-silent-lastlog"
          Feature is Disabled Using authselect Tool
        ansible.builtin.command:
          cmd: authselect disable-feature with-silent-lastlog
        register: result_authselect_disable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is search("with-silent-lastlog")

      - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_disable_feature_cmd is not skipped
        - result_authselect_disable_feature_cmd is success
      when:
      - '"pam" in ansible_facts.packages'
      - result_authselect_present.stat.exists
      - result_authselect_available_features.stdout is search("with-silent-lastlog")
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-040530
      - NIST-800-53-AC-9
      - NIST-800-53-AC-9(1)
      - PCI-DSS-Req-10.2.4
      - PCI-DSSv4-10.2.1.4
      - configure_strategy
      - display_login_attempts
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed

    - name: Ensure PAM Displays Last Logon/Access Notification - Configure pam_lastlog.so
        in appropriate PAM files
      block:

      - name: Ensure PAM Displays Last Logon/Access Notification - Define the PAM file
          to be edited as a local fact
        ansible.builtin.set_fact:
          pam_file_path: /etc/pam.d/postlogin

      - name: Ensure PAM Displays Last Logon/Access Notification - Check if system relies
          on authselect tool
        ansible.builtin.stat:
          path: /usr/bin/authselect
        register: result_authselect_present

      - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect custom
          profile is used if authselect is present
        block:

        - name: Ensure PAM Displays Last Logon/Access Notification - Check integrity of
            authselect current profile
          ansible.builtin.command:
            cmd: authselect check
          register: result_authselect_check_cmd
          changed_when: false
          failed_when: false

        - name: Ensure PAM Displays Last Logon/Access Notification - Informative message
            based on the authselect integrity check result
          ansible.builtin.assert:
            that:
            - result_authselect_check_cmd.rc == 0
            fail_msg:
            - authselect integrity check failed. Remediation aborted!
            - This remediation could not be applied because an authselect profile was
              not selected or the selected profile is not intact.
            - It is not recommended to manually edit the PAM files when authselect tool
              is available.
            - In cases where the default authselect profile does not cover a specific
              demand, a custom authselect profile is recommended.
            success_msg:
            - authselect integrity check passed

        - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
            profile
          ansible.builtin.shell:
            cmd: authselect current -r | awk '{ print $1 }'
          register: result_authselect_profile
          changed_when: false
          when:
          - result_authselect_check_cmd is success

        - name: Ensure PAM Displays Last Logon/Access Notification - Define the current
            authselect profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: '{{ result_authselect_profile.stdout }}'
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is match("custom/")

        - name: Ensure PAM Displays Last Logon/Access Notification - Define the new authselect
            custom profile as a local fact
          ansible.builtin.set_fact:
            authselect_current_profile: '{{ result_authselect_profile.stdout }}'
            authselect_custom_profile: custom/hardening
          when:
          - result_authselect_profile is not skipped
          - result_authselect_profile.stdout is not match("custom/")

        - name: Ensure PAM Displays Last Logon/Access Notification - Get authselect current
            features to also enable them in the custom profile
          ansible.builtin.shell:
            cmd: authselect current | tail -n+3 | awk '{ print $2 }'
          register: result_authselect_features
          changed_when: false
          when:
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Displays Last Logon/Access Notification - Check if any custom
            profile with the same name was already created
          ansible.builtin.stat:
            path: /etc/authselect/{{ authselect_custom_profile }}
          register: result_authselect_custom_profile_present
          changed_when: false
          when:
          - authselect_current_profile is not match("custom/")

        - name: Ensure PAM Displays Last Logon/Access Notification - Create an authselect
            custom profile based on the current profile
          ansible.builtin.command:
            cmd: authselect create-profile hardening -b {{ authselect_current_profile
              }}
          when:
          - result_authselect_check_cmd is success
          - authselect_current_profile is not match("custom/")
          - not result_authselect_custom_profile_present.stat.exists

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=before-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the authselect
            custom profile is selected
          ansible.builtin.command:
            cmd: authselect select {{ authselect_custom_profile }}
          register: result_pam_authselect_select_profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - authselect_current_profile is not match("custom/")
          - authselect_custom_profile is not match(authselect_current_profile)

        - name: Ensure PAM Displays Last Logon/Access Notification - Restore the authselect
            features in the custom profile
          ansible.builtin.command:
            cmd: authselect enable-feature {{ item }}
          loop: '{{ result_authselect_features.stdout_lines }}'
          register: result_pam_authselect_restore_features
          when:
          - result_authselect_profile is not skipped
          - result_authselect_features is not skipped
          - result_pam_authselect_select_profile is not skipped

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b --backup=after-hardening-custom-profile
          when:
          - result_authselect_check_cmd is success
          - result_authselect_profile is not skipped
          - result_pam_authselect_restore_features is not skipped

        - name: Ensure PAM Displays Last Logon/Access Notification - Change the PAM file
            to be edited according to the custom authselect profile
          ansible.builtin.set_fact:
            pam_file_path: /etc/authselect/{{ authselect_custom_profile }}/{{ pam_file_path
              | basename }}
        when:
        - result_authselect_present.stat.exists

      - name: Ensure PAM Displays Last Logon/Access Notification - Check if expected PAM
          module line is present in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*session\s+{{ 'required' | regex_escape() }}\s+pam_lastlog.so\s*.*
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_line_present

      - name: Ensure PAM Displays Last Logon/Access Notification - Include or update the
          PAM module line in {{ pam_file_path }}
        block:

        - name: Ensure PAM Displays Last Logon/Access Notification - Check if required
            PAM module line is present in {{ pam_file_path }} with different control
          ansible.builtin.lineinfile:
            path: '{{ pam_file_path }}'
            regexp: ^\s*session\s+.*\s+pam_lastlog.so\s*
            state: absent
          check_mode: true
          changed_when: false
          register: result_pam_line_other_control_present

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the correct
            control for the required PAM module line in {{ pam_file_path }}
          ansible.builtin.replace:
            dest: '{{ pam_file_path }}'
            regexp: ^(\s*session\s+).*(\bpam_lastlog.so.*)
            replace: \1required \2
          register: result_pam_module_edit
          when:
          - result_pam_line_other_control_present.found == 1

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the required
            PAM module line is included in {{ pam_file_path }}
          ansible.builtin.lineinfile:
            dest: '{{ pam_file_path }}'
            insertafter: ^\s*session\s+.*pam_succeed_if\.so.*
            line: session    required    pam_lastlog.so
          register: result_pam_module_add
          when:
          - result_pam_line_other_control_present.found == 0 or result_pam_line_other_control_present.found
            > 1

        - name: Ensure PAM Displays Last Logon/Access Notification - Ensure authselect
            changes are applied
          ansible.builtin.command:
            cmd: authselect apply-changes -b
          when:
          - result_authselect_present is defined
          - result_authselect_present.stat.exists
          - |-
            (result_pam_module_add is defined and result_pam_module_add.changed)
             or (result_pam_module_edit is defined and result_pam_module_edit.changed)
        when:
        - result_pam_line_present.found is defined
        - result_pam_line_present.found == 0

      - name: Ensure PAM Displays Last Logon/Access Notification - Check if the required
          PAM module option is present in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          regexp: ^\s*session\s+{{ 'required' | regex_escape() }}\s+pam_lastlog.so\s*.*\sshowfailed\b
          state: absent
        check_mode: true
        changed_when: false
        register: result_pam_module_showfailed_option_present

      - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "showfailed"
          PAM option for "pam_lastlog.so" is included in {{ pam_file_path }}
        ansible.builtin.lineinfile:
          path: '{{ pam_file_path }}'
          backrefs: true
          regexp: ^(\s*session\s+{{ 'required' | regex_escape() }}\s+pam_lastlog.so.*)
          line: \1 showfailed
          state: present
        register: result_pam_showfailed_add
        when:
        - result_pam_module_showfailed_option_present.found == 0

      - name: Ensure PAM Displays Last Logon/Access Notification - Ensure the "silent"
          option from "pam_lastlog.so" is not present in {{ pam_file_path }}
        ansible.builtin.replace:
          dest: '{{ pam_file_path }}'
          regexp: (.*session.*{{ 'required' | regex_escape() }}.*pam_lastlog.so.*)\bsilent\b=?[0-9a-zA-Z]*(.*)
          replace: \1\2
        register: result_pam_option_removal
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-040530
      - NIST-800-53-AC-9
      - NIST-800-53-AC-9(1)
      - PCI-DSS-Req-10.2.4
      - PCI-DSSv4-10.2.1.4
      - configure_strategy
      - display_login_attempts
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed

Group Protect Physical Console Access Group contains 3 groups and 12 rules
[ref] It is impossible to fully protect a system from an attacker with physical access, so securing the space in which the system is located should be considered a necessary step. However, there are some steps which, if taken, make it more difficult for an attacker to quickly or undetectably modify a system from its console.
Group Configure Screen Locking Group contains 2 groups and 7 rules
[ref] When a user must temporarily leave an account logged-in, screen locking should be employed to prevent passersby from abusing the account. User education and training is particularly important for screen locking to be effective, and policies can be implemented to reinforce this. Automatic screen locking is only meant as a safeguard for those cases where a user forgot to lock the screen.
Group Configure Console Screen Locking Group contains 1 rule

[ref] A console screen locking mechanism is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.

#### Rule Install the screen Package [ref]

To enable console screen locking, install the `screen` package. The `screen` package can be installed with the following command:

    $ sudo yum install screen

Instruct users to begin new terminal sessions with the following command:

    $ screen

The console can now be locked with the following key combination:

    ctrl+a x

Rationale:

A session time-out lock is a temporary action taken when a user stops work and moves away from the immediate physical vicinity of the information system but does not logout because of the temporary nature of the absence. Rather than relying on the user to manually lock their operation system session prior to vacating the vicinity, operating systems need to be able to identify when a user's session has idled and take action to initiate the session lock.
The `screen` package allows for a session lock to be implemented and configured.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_screen_installed

Identifiers and References

References: 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.10, CCI-000057, CCI-000058, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), PR.AC-7, FMT_MOF_EXT.1, SRG-OS-000029-GPOS-00010, OL07-00-010090, SV-255900r880615_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "screen" ; then
        yum install -y "screen"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    package --add=screen

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Ensure screen is installed
      package:
        name: screen
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010090
      - NIST-800-171-3.1.10
      - NIST-800-53-CM-6(a)
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_screen_installed

Remediation OSBuild Blueprint snippet ⇲

    [[packages]]
    name = "screen"
    version = "*"

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include install_screen

    class install_screen {
      package { 'screen':
        ensure => 'installed',
      }
    }

Group Hardware Tokens for Authentication Group contains 6 rules
[ref] The use of hardware tokens such as smart cards for system login provides stronger, two-factor authentication than using a username and password. In Oracle Linux 7 servers, hardware token login is not enabled by default and must be enabled in the system settings.

#### Rule Install the opensc Package For Multifactor Authentication [ref]

The `opensc` package can be installed with the following command:

    $ sudo yum install opensc

Rationale:

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.
Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_opensc_installed
Identifiers and References | References: CCI-001954, CCI-001953, 1382, 1384, 1386, CM-6(a), SRG-OS-000375-GPOS-00160, SRG-OS-000376-GPOS-00161

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "opensc" ; then
        yum install -y "opensc"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    package --add=opensc

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Ensure opensc is installed
      package:
        name: opensc
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_opensc_installed

Remediation OSBuild Blueprint snippet ⇲

    [[packages]]
    name = "opensc"
    version = "*"

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include install_opensc

    class install_opensc {
      package { 'opensc':
        ensure => 'installed',
      }
    }

#### Rule Install the pcsc-lite package [ref]

The `pcsc-lite` package can be installed with the following command:

    $ sudo yum install pcsc-lite

Rationale: | The pcsc-lite package must be installed if it is to be available for multifactor authentication using smartcards.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_pcsc-lite_installed
Identifiers and References | References: CCI-001954, 1382, 1384, 1386, CM-6(a), SRG-OS-000375-GPOS-00160

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "pcsc-lite" ; then
        yum install -y "pcsc-lite"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    package --add=pcsc-lite

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Ensure pcsc-lite is installed
      package:
        name: pcsc-lite
        state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_pcsc-lite_installed

Remediation OSBuild Blueprint snippet ⇲

    [[packages]]
    name = "pcsc-lite"
    version = "*"

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include install_pcsc-lite

    class install_pcsc-lite {
      package { 'pcsc-lite':
        ensure => 'installed',
      }
    }

#### Rule Enable the pcscd Service [ref]

The `pcscd` service can be enabled with the following command:

    $ sudo systemctl enable pcscd.service

Rationale:

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.
Multifactor solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_pcscd_enabled
Identifiers and References | References: CCI-001954, 1382, 1384, 1386, IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a), Req-8.3, SRG-OS-000375-GPOS-00160

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" unmask 'pcscd.service'
    "$SYSTEMCTL_EXEC" start 'pcscd.service'
    "$SYSTEMCTL_EXEC" enable 'pcscd.service'

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Enable service pcscd
      block:

      - name: Gather the package facts
        package_facts:
          manager: auto

      - name: Start service pcscd
        systemd:
          name: pcscd
          state: started
          masked: 'no'
        when:
        - '"pcsc-lite" in ansible_facts.packages'

      - name: Enable service pcscd
        ansible.builtin.command:
          cmd: systemctl enable pcscd
        when:
        - '"pcsc-lite" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_pcscd_enabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    enabled = ["pcscd"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include enable_pcscd

    class enable_pcscd {
      service {'pcscd':
        enable => true,
        ensure => 'running',
      }
    }

#### Rule Configure opensc Smart Card Drivers [ref]

The OpenSC smart card tool can auto-detect smart card drivers; however, setting the smart card drivers in use by your organization helps to prevent users from using unauthorized smart cards. The default smart card driver for this profile is `cac`. To configure the OpenSC driver, edit the `/etc/opensc.conf` and add the following line into the file in the `app default` block, so it will look like:

    app default {
       ...
       card_drivers = cac;
    }

Rationale: | Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials. Configuring the smart card driver in use by your organization helps to prevent users from using unauthorized smart cards.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_configure_opensc_card_drivers

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000771, CCI-000772, CCI-000884, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 1382, 1384, 1386, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.3, SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000108-GPOS-00057, SRG-OS-000108-GPOS-00058

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_smartcard_drivers='cac'

    OPENSC_TOOL="/usr/bin/opensc-tool"

    if [ -f "${OPENSC_TOOL}" ]; then
        ${OPENSC_TOOL} -S app:default:card_drivers:$var_smartcard_drivers
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_smartcard_drivers # promote to variable
      set_fact:
        var_smartcard_drivers: !!str cac
      tags:
        - always

    - name: Check existence of opensc conf
      stat:
        path: /etc/opensc-{{ ansible_architecture }}.conf
      register: opensc_conf_cd
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_opensc_card_drivers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Configure smartcard driver block
      block:

      - name: Check if card_drivers is defined
        command: /usr/bin/opensc-tool -G app:default:card_drivers
        changed_when: false
        register: card_drivers

      - name: Configure opensc Smart Card Drivers
        command: |
          /usr/bin/opensc-tool -S app:default:card_drivers:{{ var_smartcard_drivers }}
        when:
        - card_drivers.stdout != var_smartcard_drivers
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - opensc_conf_cd.stat.exists
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_opensc_card_drivers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Configure NSS DB To Use opensc [ref]

The `opensc` module should be configured for use over the `Coolkey PKCS#11` module in the NSS database. To configure the NSS database to use the `opensc` module, run the following command:

    $ sudo pkcs11-switch opensc

Warning: NSS modules information are stored in NSS database which is in binary format. Currently it is not possible to check NSS database using OVAL. This is the reason there is no OVAL check for this rule.

Rationale: | Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_configure_opensc_nss_db

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000771, CCI-000772, CCI-000884, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.3, SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000108-GPOS-00057, SRG-OS-000108-GPOS-00058

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    PKCSSW=$(/usr/bin/pkcs11-switch)

    if [ ${PKCSSW} != "opensc" ] ; then
        echo -e "\n" | ${PKCSSW} opensc
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Configure NSS DB To Use opensc - Check Existence of pkcs11-switch
      ansible.builtin.stat:
        path: /usr/bin/pkcs11-switch
      register: pkcs11switch
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_opensc_nss_db
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Configure NSS DB To Use opensc - Get NSS Database Smart Card Configuration
      ansible.builtin.command: /usr/bin/pkcs11-switch
      changed_when: true
      register: pkcsw_output
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - pkcs11switch.stat.exists
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_opensc_nss_db
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Configure NSS DB To Use opensc - Select opensc Module
      ansible.builtin.shell: echo -e "\n" | /usr/bin/pkcs11-switch opensc
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - pkcs11switch.stat.exists and pkcsw_output.stdout != "opensc"
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_opensc_nss_db
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Force opensc To Use Defined Smart Card Driver [ref]

The OpenSC smart card middleware can auto-detect smart card drivers; however by forcing the smart card driver in use by your organization, opensc will no longer autodetect or use other drivers unless specified. This helps to prevent users from using unauthorized smart cards. The default smart card driver for this profile is `cac`. To force the OpenSC driver, edit the `/etc/opensc.conf`. Look for a line similar to:

    # force_card_driver = customcos;

and change it to:

    force_card_driver = cac;

Rationale: | Smart card login provides two-factor authentication stronger than that provided by a username and password combination. Smart cards leverage PKI (public key infrastructure) in order to provide and verify credentials. Forcing the smart card driver in use by your organization helps to prevent users from using unauthorized smart cards.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_force_opensc_card_drivers

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000765, CCI-000766, CCI-000767, CCI-000768, CCI-000771, CCI-000772, CCI-000884, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 1382, 1384, 1386, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-2(1), IA-2(2), IA-2(3), IA-2(4), IA-2(6), IA-2(7), IA-2(11), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.3, SRG-OS-000104-GPOS-00051, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000109-GPOS-00056, SRG-OS-000108-GPOS-00055, SRG-OS-000108-GPOS-00057, SRG-OS-000108-GPOS-00058

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_smartcard_drivers='cac'

    OPENSC_TOOL="/usr/bin/opensc-tool"

    if [ -f "${OPENSC_TOOL}" ]; then
        ${OPENSC_TOOL} -S app:default:force_card_driver:$var_smartcard_drivers
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_smartcard_drivers # promote to variable
      set_fact:
        var_smartcard_drivers: !!str cac
      tags:
        - always

    - name: Check existence of opensc conf
      stat:
        path: /etc/opensc-{{ ansible_architecture }}.conf
      register: opensc_conf_fcd
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_strategy
      - force_opensc_card_drivers
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Force smartcard driver block
      block:

      - name: Check if force_card_driver is defined
        command: /usr/bin/opensc-tool -G app:default:force_card_driver
        changed_when: false
        register: force_card_driver

      - name: Force opensc To Use Defined Smart Card Driver
        command: |
          /usr/bin/opensc-tool -S app:default:force_card_driver:{{ var_smartcard_drivers }}
        when:
        - force_card_driver.stdout != var_smartcard_drivers
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - opensc_conf_fcd.stat.exists
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2(1)
      - NIST-800-53-IA-2(11)
      - NIST-800-53-IA-2(2)
      - NIST-800-53-IA-2(3)
      - NIST-800-53-IA-2(4)
      - NIST-800-53-IA-2(6)
      - NIST-800-53-IA-2(7)
      - PCI-DSS-Req-8.3
      - configure_strategy
      - force_opensc_card_drivers
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Disable debug-shell SystemD Service [ref]

SystemD's `debug-shell` service is intended to diagnose SystemD related boot issues with various `systemctl` commands. Once enabled and following a system reboot, the root shell will be available on `tty9` which is access by pressing `CTRL-ALT-F9`. The `debug-shell` service should only be used for SystemD related issues and should otherwise be disabled.
By default, the `debug-shell` SystemD service is already disabled. The `debug-shell` service can be disabled with the following command:

    $ sudo systemctl mask --now debug-shell.service

Rationale: | This prevents attackers with physical access from trivially bypassing security on the machine through valid troubleshooting configurations and gaining root access when the system is rebooted.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_debug-shell_disabled
Identifiers and References | References: 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), CM-6, FIA_UAU.1, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'debug-shell.service'
    "$SYSTEMCTL_EXEC" disable 'debug-shell.service'
    "$SYSTEMCTL_EXEC" mask 'debug-shell.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files debug-shell.socket; then
        "$SYSTEMCTL_EXEC" stop 'debug-shell.socket'
        "$SYSTEMCTL_EXEC" mask 'debug-shell.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'debug-shell.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service debug-shell
      block:

      - name: Disable service debug-shell
        block:

        - name: Disable service debug-shell
          systemd:
            name: debug-shell.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service debug-shell' failure,
            service was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_debug-shell_disabled

    - name: Unit Socket Exists - debug-shell.socket
      command: systemctl -q list-unit-files debug-shell.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_debug-shell_disabled

    - name: Disable socket debug-shell
      systemd:
        name: debug-shell.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("debug-shell.socket",multiline=True)
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_debug-shell_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["debug-shell"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_debug-shell

    class disable_debug-shell {
      service {'debug-shell':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Disable Ctrl-Alt-Del Burst Action [ref]

By default, `SystemD` will reboot the system if the `Ctrl-Alt-Del` key sequence is pressed Ctrl-Alt-Delete more than 7 times in 2 seconds.
To configure the system to ignore the `CtrlAltDelBurstAction` setting, add or modify the following to `/etc/systemd/system.conf`:

    CtrlAltDelBurstAction=none

Warning: Disabling the `Ctrl-Alt-Del` key sequence in `/etc/init/control-alt-delete.conf` DOES NOT disable the `Ctrl-Alt-Del` key sequence if running in `runlevel 6` (e.g. in GNOME, KDE, etc.)! The `Ctrl-Alt-Del` key sequence will only be disabled if running in the non-graphical `runlevel 3`.

Rationale: | A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_burstaction

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), CM-6(a), PR.AC-4, PR.DS-5, FAU_GEN.1.2, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q systemd; }; then

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^CtrlAltDelBurstAction=")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s=%s" "$stripped_key" "none"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^CtrlAltDelBurstAction=\\>" "/etc/systemd/system.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^CtrlAltDelBurstAction=\\>.*/$escaped_formatted_output/gi" "/etc/systemd/system.conf"
    else
        if [[ -s "/etc/systemd/system.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/systemd/system.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/systemd/system.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/systemd/system.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(a)
      - disable_ctrlaltdel_burstaction
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed

    - name: Disable Ctrl-Alt-Del Burst Action
      lineinfile:
        dest: /etc/systemd/system.conf
        state: present
        regexp: ^CtrlAltDelBurstAction
        line: CtrlAltDelBurstAction=none
        create: true
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"systemd" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(a)
      - disable_ctrlaltdel_burstaction
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed

#### Rule Disable Ctrl-Alt-Del Reboot Activation [ref]

By default, `SystemD` will reboot the system if the `Ctrl-Alt-Del` key sequence is pressed.
To configure the system to ignore the `Ctrl-Alt-Del` key sequence from the command line instead of rebooting the system, do either of the following:

    ln -sf /dev/null /etc/systemd/system/ctrl-alt-del.target

or

    systemctl mask ctrl-alt-del.target

Do not simply delete the `/usr/lib/systemd/system/ctrl-alt-del.service` file, as this file may be restored during future system updates.

Rationale: | A locally logged-in user who presses Ctrl-Alt-Del, when at the console, can reboot the system. If accidentally pressed, as could happen in the case of mixed OS environment, this can create the risk of short-term loss of availability of systems due to unintentional reboot.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_disable_ctrlaltdel_reboot

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, FAU_GEN.1.2, SRG-OS-000324-GPOS-00125, SRG-OS-000480-GPOS-00227, OL07-00-020230, SV-221717r928540_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    systemctl disable --now ctrl-alt-del.target
    systemctl mask --now ctrl-alt-del.target

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Disable Ctrl-Alt-Del Reboot Activation
      systemd:
        name: ctrl-alt-del.target
        force: true
        masked: true
        state: stopped
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020230
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_ctrlaltdel_reboot
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed

#### Rule Verify that Interactive Boot is Disabled [ref]

Oracle Linux 7 systems support an "interactive boot" option that can be used to prevent services from being started. On a Oracle Linux 7 system, interactive boot can be enabled by providing a `1`, `yes`, `true`, or `on` value to the `systemd.confirm_spawn` kernel argument in `/etc/default/grub`. Remove any instance of

    systemd.confirm_spawn=(1|yes|true|on)

from the kernel arguments in that file to disable interactive boot. Recovery booting must also be disabled. Confirm that `GRUB_DISABLE_RECOVERY=true` is set in `/etc/default/grub`. It is also required to change the runtime configuration, run:

    /sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"

    grub2-mkconfig -o /boot/grub2/grub.cfg

Rationale: | Using interactive or recovery boot, the console user could disable auditing, firewalls, or other services, weakening system security.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_disable_interactive_boot

Identifiers and References

References: 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.2, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, SC-2(1), CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_UAU.1, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    # Verify that Interactive Boot is Disabled in /etc/default/grub
    CONFIRM_SPAWN_YES="systemd.confirm_spawn\(=\(1\|yes\|true\|on\)\|\b\)"
    CONFIRM_SPAWN_NO="systemd.confirm_spawn=no"

    if grep -q "\(GRUB_CMDLINE_LINUX\|GRUB_CMDLINE_LINUX_DEFAULT\)" /etc/default/grub
    then
    	sed -i "s/${CONFIRM_SPAWN_YES}/${CONFIRM_SPAWN_NO}/" /etc/default/grub
    fi

    # make sure GRUB_DISABLE_RECOVERY=true
    if grep -q '^GRUB_DISABLE_RECOVERY=.*'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an GRUB_DISABLE_RECOVERY= arg already exists
           sed -i 's/GRUB_DISABLE_RECOVERY=.*/GRUB_DISABLE_RECOVERY=true/' /etc/default/grub
    else
           # no GRUB_DISABLE_RECOVERY=arg is present, append it to file
           echo "GRUB_DISABLE_RECOVERY=true"  >> '/etc/default/grub'
    fi

    # Remove 'systemd.confirm_spawn' kernel argument also from runtime settings
    /sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"

    #Regen grub.cfg handle updated GRUB_DISABLE_RECOVERY and confirm_spawn
    grub2-mkconfig -o /boot/grub2/grub.cfg

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-2(1)
      - grub2_disable_interactive_boot
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Verify GRUB_DISABLE_RECOVERY=true
      lineinfile:
        path: /etc/default/grub
        regexp: ^GRUB_DISABLE_RECOVERY=.*
        line: GRUB_DISABLE_RECOVERY=true
        state: present
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-2(1)
      - grub2_disable_interactive_boot
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Verify that Interactive Boot is Disabled in /etc/default/grub
      replace:
        dest: /etc/default/grub
        regexp: systemd.confirm_spawn(=(1|yes|true|on)|\b)
        replace: systemd.confirm_spawn=no
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-2(1)
      - grub2_disable_interactive_boot
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Verify that Interactive Boot is Disabled (runtime)
      command: /sbin/grubby --update-kernel=ALL --remove-args="systemd.confirm_spawn"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-2(1)
      - grub2_disable_interactive_boot
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Regen grub.cfg handle updated GRUB_DISABLE_RECOVERY and confirm_spawn
      command: grub2-mkconfig -o  /boot/grub2/grub.cfg
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.4.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-2(1)
      - grub2_disable_interactive_boot
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Require Authentication for Single User Mode [ref]

Single-user mode is intended as a system recovery method, providing a single user root access to the system by providing a boot option at startup. By default, single-user mode is protected by requiring a password and is set in `/usr/lib/systemd/system/rescue.service`.
Rationale: | This prevents attackers with physical access from trivially bypassing security on the machine and gaining root access. Such accesses are further prevented by configuring the bootloader password.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_require_singleuser_auth

Identifiers and References

References: 1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-3, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, OL07-00-010481, SV-221699r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    service_file="/usr/lib/systemd/system/rescue.service"

    sulogin='/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block default"'

    if grep "^ExecStart=.*" "$service_file" ; then
        sed -i "s%^ExecStart=.*%ExecStart=-$sulogin%" "$service_file"
    else
        echo "ExecStart=-$sulogin" >> "$service_file"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Require single user mode password
      lineinfile:
        create: true
        dest: /usr/lib/systemd/system/rescue.service
        regexp: ^#?ExecStart=
        line: ExecStart=-/bin/sh -c "/sbin/sulogin; /usr/bin/systemctl --fail --no-block
          default"
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010481
      - NIST-800-171-3.1.1
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-3
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - require_singleuser_auth
      - restrict_strategy

Group Protect Accounts by Restricting Password-Based Login Group contains 4 groups and 12 rules

[ref] Conventionally, Unix shell accounts are accessed by providing a username and password to a login program, which tests these values for correctness using the `/etc/passwd` and `/etc/shadow` files. Password-based login is vulnerable to guessing of weak passwords, and to sniffing and man-in-the-middle attacks against passwords entered over a network or at an insecure console. Therefore, mechanisms for accessing accounts by entering usernames and passwords should be restricted to those which are operationally necessary.

Group Set Account Expiration Parameters Group contains 1 rule

[ref] Accounts can be configured to be automatically disabled after a certain time period, meaning that they will require administrator interaction to become usable again. Expiration of accounts after inactivity can be set for all accounts by default and also on a per-account basis, such as for accounts that are known to be temporary. To configure automatic expiration of an account following the expiration of its password (that is, after the password has expired and not been changed), run the following command, substituting `NUM_DAYS` and `USER` appropriately:

    $ sudo chage -I NUM_DAYS USER

Accounts, such as temporary accounts, can also be configured to expire on an explicitly-set date with the `-E` option. The file `/etc/default/useradd` controls default settings for all newly-created accounts created with the system's normal command line utilities.
Warning: This will only apply to newly created accounts

#### Rule Set Account Expiration Following Inactivity [ref]

To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following line in `/etc/default/useradd`:

    INACTIVE=35

If a password is currently on the verge of expiration, then `35` day(s) remain(s) until the account is automatically disabled. However, if the password will not expire for another 60 days, then 60 days plus `35` day(s) could elapse until the account would be automatically disabled. See the `useradd` man page for more information.

Rationale:

Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_account_disable_post_pw_expiration

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.6.2.1.1, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000017, CCI-000795, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, IA-4(e), AC-2(3), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.1.4, 8.2.6, SRG-OS-000118-GPOS-00060, OL07-00-010310, SV-221689r928639_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_account_disable_post_pw_expiration='35'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^INACTIVE")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s=%s" "$stripped_key" "$var_account_disable_post_pw_expiration"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^INACTIVE\\>" "/etc/default/useradd"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^INACTIVE\\>.*/$escaped_formatted_output/gi" "/etc/default/useradd"
    else
        if [[ -s "/etc/default/useradd" ]] && [[ -n "$(tail -c 1 -- "/etc/default/useradd" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/default/useradd"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/default/useradd"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010310
      - NIST-800-171-3.5.6
      - NIST-800-53-AC-2(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-4(e)
      - PCI-DSS-Req-8.1.4
      - PCI-DSSv4-8.2.6
      - account_disable_post_pw_expiration
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_account_disable_post_pw_expiration # promote to variable
      set_fact:
        var_account_disable_post_pw_expiration: !!str 35
      tags:
        - always

    - name: Set Account Expiration Following Inactivity
      lineinfile:
        create: true
        dest: /etc/default/useradd
        regexp: ^INACTIVE
        line: INACTIVE={{ var_account_disable_post_pw_expiration }}
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010310
      - NIST-800-171-3.5.6
      - NIST-800-53-AC-2(3)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-4(e)
      - PCI-DSS-Req-8.1.4
      - PCI-DSSv4-8.2.6
      - account_disable_post_pw_expiration
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Set Password Expiration Parameters Group contains 4 rules

[ref] The file `/etc/login.defs` controls several password-related settings. Programs such as `passwd`, `su`, and `login` consult `/etc/login.defs` to determine behavior with regard to password aging, expiration warnings, and length. See the man page `login.defs(5)` for more information.
Users should be forced to change their passwords, in order to decrease the utility of compromised passwords. However, the need to change passwords often should be balanced against the risk that users will reuse or write down passwords if forced to change them too often. Forcing password changes every 90-360 days, depending on the environment, is recommended. Set the appropriate value as `PASS_MAX_DAYS` and apply it to existing accounts with the `-M` flag.
The `PASS_MIN_DAYS` (`-m`) setting prevents password changes for 7 days after the first change, to discourage password cycling. If you use this setting, train users to contact an administrator for an emergency password change in case a new password becomes compromised. The `PASS_WARN_AGE` (`-W`) setting gives users 7 days of warnings at login time that their passwords are about to expire.
For example, for each existing human user USER, expiration parameters could be adjusted to a 180 day maximum password age, 7 day minimum password age, and 7 day warning period with the following command:

    $ sudo chage -M 180 -m 7 -W 7 USER

#### Rule Set Password Maximum Age [ref]

To specify password maximum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MAX_DAYS 60

A value of 180 days is sufficient for many environments. The DoD requirement is 60. The profile requirement is `60`.

Rationale:

Any password, no matter how complex, can eventually be cracked. Therefore, passwords need to be changed periodically. If the operating system does not limit the lifetime of passwords and force users to change their passwords, there is the risk that the operating system passwords could be compromised.
Setting the password maximum age ensures users are required to periodically change their passwords. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_maximum_age_login_defs

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.6, CCI-000199, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.4, 8.3.9, SRG-OS-000076-GPOS-00044, OL07-00-010250, SV-221683r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_maximum_age_login_defs='60'

    grep -q ^PASS_MAX_DAYS /etc/login.defs && \
      sed -i "s/PASS_MAX_DAYS.*/PASS_MAX_DAYS     $var_accounts_maximum_age_login_defs/g" /etc/login.defs
    if ! [ $? -eq 0 ]; then
        echo "PASS_MAX_DAYS      $var_accounts_maximum_age_login_defs" >> /etc/login.defs
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1
      - DISA-STIG-OL07-00-010250
      - NIST-800-171-3.5.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.4
      - PCI-DSSv4-8.3.9
      - accounts_maximum_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_maximum_age_login_defs # promote to variable
      set_fact:
        var_accounts_maximum_age_login_defs: !!str 60
      tags:
        - always

    - name: Set Password Maximum Age
      lineinfile:
        create: true
        dest: /etc/login.defs
        regexp: ^#?PASS_MAX_DAYS
        line: PASS_MAX_DAYS {{ var_accounts_maximum_age_login_defs }}
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1
      - DISA-STIG-OL07-00-010250
      - NIST-800-171-3.5.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.4
      - PCI-DSSv4-8.3.9
      - accounts_maximum_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Password Minimum Age [ref]

To specify password minimum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MIN_DAYS 7

A value of 1 day is considered sufficient for many environments. The DoD requirement is 1. The profile requirement is `7`.

Rationale:

Enforcing a minimum password lifetime helps to prevent repeated password changes to defeat the password reuse or history enforcement requirement. If users are allowed to immediately and continually change their password, then the password could be repeatedly changed in a short period of time to defeat the organization's policy regarding password reuse.
Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_minimum_age_login_defs

Identifiers and References

References: 1, 12, 15, 16, 5, 5.6.2.1.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, CCI-000198, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0418, 1055, 1402, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(d), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000075-GPOS-00043, OL07-00-010230, SV-221681r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_minimum_age_login_defs='7'

    grep -q ^PASS_MIN_DAYS /etc/login.defs && \
      sed -i "s/PASS_MIN_DAYS.*/PASS_MIN_DAYS     $var_accounts_minimum_age_login_defs/g" /etc/login.defs
    if ! [ $? -eq 0 ]; then
        echo "PASS_MIN_DAYS      $var_accounts_minimum_age_login_defs" >> /etc/login.defs
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010230
      - NIST-800-171-3.5.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - accounts_minimum_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_minimum_age_login_defs # promote to variable
      set_fact:
        var_accounts_minimum_age_login_defs: !!str 7
      tags:
        - always

    - name: Set Password Minimum Age
      lineinfile:
        create: true
        dest: /etc/login.defs
        regexp: ^#?PASS_MIN_DAYS
        line: PASS_MIN_DAYS {{ var_accounts_minimum_age_login_defs }}
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1.1
      - DISA-STIG-OL07-00-010230
      - NIST-800-171-3.5.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - accounts_minimum_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Password Minimum Length in login.defs [ref]

To specify password length requirements for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MIN_LEN 6

The DoD requirement is `15`. The FISMA requirement is `12`. The profile requirement is `6`. If a program consults `/etc/login.defs` and also another PAM module (such as `pam_pwquality`) during a password change operation, then the most restrictive must be satisfied. See PAM section for more information about enforcing password quality requirements.

Rationale: | Requiring a minimum password length makes password cracking attacks more difficult by ensuring a larger search space. However, any security benefit from an onerous requirement must be carefully weighed against usability problems, support costs, or counterproductive behavior that may result.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_minlen_login_defs

Identifiers and References

References: BP28(R18), 1, 12, 15, 16, 5, 5.6.2.1, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.7, CCI-000205, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(f), IA-5(1)(a), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000078-GPOS-00046

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_password_minlen_login_defs='6'

    grep -q ^PASS_MIN_LEN /etc/login.defs && \
    sed -i "s/PASS_MIN_LEN.*/PASS_MIN_LEN\t$var_accounts_password_minlen_login_defs/g" /etc/login.defs
    if ! [ $? -eq 0 ]
    then
      echo -e "PASS_MIN_LEN\t$var_accounts_password_minlen_login_defs" >> /etc/login.defs
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.6.2.1
      - NIST-800-171-3.5.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(f)
      - accounts_password_minlen_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_password_minlen_login_defs # promote to variable
      set_fact:
        var_accounts_password_minlen_login_defs: !!str 6
      tags:
        - always

    - name: Set Password Minimum Length in login.defs
      lineinfile:
        dest: /etc/login.defs
        regexp: ^PASS_MIN_LEN *[0-9]*
        state: present
        line: PASS_MIN_LEN        {{ var_accounts_password_minlen_login_defs }}
        create: true
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - CJIS-5.6.2.1
      - NIST-800-171-3.5.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(f)
      - accounts_password_minlen_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Password Warning Age [ref]

To specify how many days prior to password expiration that a warning will be issued to users, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_WARN_AGE 7

The DoD requirement is 7. The profile requirement is `7`.

Rationale: | Setting the password warning age enables users to make the change at a practical time.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_warn_age_login_defs

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.8, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, 0418, 1055, 1402, A.12.4.1, A.12.4.3, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(f), IA-5(1)(d), CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, Req-8.2.4, 8.3.9

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_password_warn_age_login_defs='7'

    grep -q ^PASS_WARN_AGE /etc/login.defs && \
    sed -i "s/PASS_WARN_AGE.*/PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs/g" /etc/login.defs
    if ! [ $? -eq 0 ]
    then
      echo -e "PASS_WARN_AGE\t$var_accounts_password_warn_age_login_defs" >> /etc/login.defs
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.5.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.4
      - PCI-DSSv4-8.3.9
      - accounts_password_warn_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_password_warn_age_login_defs # promote to variable
      set_fact:
        var_accounts_password_warn_age_login_defs: !!str 7
      tags:
        - always

    - name: Set Password Warning Age
      lineinfile:
        dest: /etc/login.defs
        regexp: ^PASS_WARN_AGE *[0-9]*
        state: present
        line: PASS_WARN_AGE        {{ var_accounts_password_warn_age_login_defs }}
        create: true
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.5.8
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(d)
      - NIST-800-53-IA-5(f)
      - PCI-DSS-Req-8.2.4
      - PCI-DSSv4-8.3.9
      - accounts_password_warn_age_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Verify Proper Storage and Existence of Password Hashes Group contains 3 rules

[ref] By default, password hashes for local accounts are stored in the second field (colon-separated) in `/etc/shadow`. This file should be readable only by processes running with root credentials, preventing users from casually accessing others' password hashes and attempting to crack them. However, it remains possible to misconfigure the system and store password hashes in world-readable files such as `/etc/passwd`, or to even store passwords themselves in plaintext on the system. Using system-provided tools for password change/creation should allow administrators to avoid such misconfiguration.

#### Rule Verify All Account Password Hashes are Shadowed [ref]

If any password hashes are stored in `/etc/passwd` (in the second field, instead of an `x` or `*`), the cause of this misconfiguration should be investigated. The account should have its password reset and the hash should be properly stored, or the account should be deleted entirely.
Rationale: | The hashes for all user account passwords should be stored in the file `/etc/shadow` and never in `/etc/passwd`, which is readable by all users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_password_all_shadowed

Identifiers and References

References: 1, 12, 15, 16, 5, 5.5.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.5.10, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, 1410, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, IA-5(h), CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.2.1, 8.3.2

#### Rule All GIDs referenced in /etc/passwd must be defined in /etc/group [ref]

Add a group to the system for each GID referenced without a corresponding group.
Rationale: | If a user is assigned the Group Identifier (GID) of a group not existing on the system, and a group with the Group Identifier (GID) is subsequently created, the user may have unintended rights to any files associated with the group.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_gid_passwd_group_same

Identifiers and References

References: 1, 12, 15, 16, 5, 5.5.2, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-000764, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, Req-8.5.a, 8.2.2, SRG-OS-000104-GPOS-00051, OL07-00-020300, SV-221722r603260_rule

#### Rule Prevent Login to Accounts With Empty Password [ref]

If an account is configured for password authentication but does not have an assigned password, it may be possible to log into the account without authentication. Remove any instances of the `nullok` in `/etc/pam.d/system-auth` and `/etc/pam.d/password-auth` to prevent logins with empty passwords.
Warning: If the system relies on `authselect` tool to manage PAM settings, the remediation will also use `authselect` tool. However, if any manual modification was made in PAM files, the `authselect` integrity check will fail and the remediation will be aborted in order to preserve intentional changes. In this case, an informative message will be shown in the remediation report. Note that this rule is not applicable for systems running within a container. Having user with empty password within a container is not considered a risk, because it should not be possible to directly login into a container anyway.

Rationale: | If an account has an empty password, anyone could log in and run commands with the privileges of that account. Accounts with empty passwords should never be used in operational environments.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_no_empty_passwords

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, IA-5(1)(a), IA-5(c), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, FIA_UAU.1, Req-8.2.3, 8.3.1, SRG-OS-000480-GPOS-00227, OL07-00-010290, SV-221687r880678_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -f /usr/bin/authselect ]; then
        if ! authselect check; then
    echo "
    authselect integrity check failed. Remediation aborted!
    This remediation could not be applied because an authselect profile was not selected or the selected profile is not intact.
    It is not recommended to manually edit the PAM files when authselect tool is available.
    In cases where the default authselect profile does not cover a specific demand, a custom authselect profile is recommended."
    exit 1
    fi
    authselect enable-feature without-nullok

    authselect apply-changes -b
    else

    if grep -qP '^\s*auth\s+'"sufficient"'\s+pam_unix.so\s.*\bnullok\b' "/etc/pam.d/system-auth"; then
        sed -i -E --follow-symlinks 's/(.*auth.*'"sufficient"'.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g' "/etc/pam.d/system-auth"
    fi

    if grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s.*\bnullok\b' "/etc/pam.d/system-auth"; then
        sed -i -E --follow-symlinks 's/(.*password.*'"sufficient"'.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g' "/etc/pam.d/system-auth"
    fi

    if grep -qP '^\s*auth\s+'"sufficient"'\s+pam_unix.so\s.*\bnullok\b' "/etc/pam.d/password-auth"; then
        sed -i -E --follow-symlinks 's/(.*auth.*'"sufficient"'.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g' "/etc/pam.d/password-auth"
    fi

    if grep -qP '^\s*password\s+'"sufficient"'\s+pam_unix.so\s.*\bnullok\b' "/etc/pam.d/password-auth"; then
        sed -i -E --follow-symlinks 's/(.*password.*'"sufficient"'.*pam_unix.so.*)\snullok=?[[:alnum:]]*(.*)/\1\2/g' "/etc/pam.d/password-auth"
    fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Prevent Login to Accounts With Empty Password - Check if system relies on
        authselect
      ansible.builtin.stat:
        path: /usr/bin/authselect
      register: result_authselect_present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-010290
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.1
      - configure_strategy
      - high_severity
      - low_complexity
      - medium_disruption
      - no_empty_passwords
      - no_reboot_needed

    - name: Prevent Login to Accounts With Empty Password - Remediate using authselect
      block:

      - name: Prevent Login to Accounts With Empty Password - Check integrity of authselect
          current profile
        ansible.builtin.command:
          cmd: authselect check
        register: result_authselect_check_cmd
        changed_when: false
        failed_when: false

      - name: Prevent Login to Accounts With Empty Password - Informative message based
          on the authselect integrity check result
        ansible.builtin.assert:
          that:
          - result_authselect_check_cmd.rc == 0
          fail_msg:
          - authselect integrity check failed. Remediation aborted!
          - This remediation could not be applied because an authselect profile was not
            selected or the selected profile is not intact.
          - It is not recommended to manually edit the PAM files when authselect tool
            is available.
          - In cases where the default authselect profile does not cover a specific demand,
            a custom authselect profile is recommended.
          success_msg:
          - authselect integrity check passed

      - name: Prevent Login to Accounts With Empty Password - Get authselect current features
        ansible.builtin.shell:
          cmd: authselect current | tail -n+3 | awk '{ print $2 }'
        register: result_authselect_features
        changed_when: false
        when:
        - result_authselect_check_cmd is success

      - name: Prevent Login to Accounts With Empty Password - Ensure "without-nullok"
          feature is enabled using authselect tool
        ansible.builtin.command:
          cmd: authselect enable-feature without-nullok
        register: result_authselect_enable_feature_cmd
        when:
        - result_authselect_check_cmd is success
        - result_authselect_features.stdout is not search("without-nullok")

      - name: Prevent Login to Accounts With Empty Password - Ensure authselect changes
          are applied
        ansible.builtin.command:
          cmd: authselect apply-changes -b
        when:
        - result_authselect_enable_feature_cmd is not skipped
        - result_authselect_enable_feature_cmd is success
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-010290
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.1
      - configure_strategy
      - high_severity
      - low_complexity
      - medium_disruption
      - no_empty_passwords
      - no_reboot_needed

    - name: Prevent Login to Accounts With Empty Password - Remediate directly editing
        PAM files
      ansible.builtin.replace:
        dest: '{{ item }}'
        regexp: nullok
      loop:
      - /etc/pam.d/system-auth
      - /etc/pam.d/password-auth
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not result_authselect_present.stat.exists
      tags:
      - CJIS-5.5.2
      - DISA-STIG-OL07-00-010290
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(a)
      - NIST-800-53-IA-5(c)
      - PCI-DSS-Req-8.2.3
      - PCI-DSSv4-8.3.1
      - configure_strategy
      - high_severity
      - low_complexity
      - medium_disruption
      - no_empty_passwords
      - no_reboot_needed

Remediation Kubernetes snippet ⇲

    ---
    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    spec:
      config:
        ignition:
          version: 3.1.0
        storage:
          files:
          - contents:
              source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
            mode: 0644
            path: /etc/pam.d/password-auth
            overwrite: true
          - contents:
              source: data:,%23%20Generated%20by%20authselect%20on%20Sat%20Oct%2027%2014%3A59%3A36%202018%0A%23%20Do%20not%20modify%20this%20file%20manually.%0A%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_env.so%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_faildelay.so%20delay%3D2000000%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_fprintd.so%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet%0Aauth%20%20%20%20%20%20%20%20%5Bdefault%3D1%20ignore%3Dignore%20success%3Dok%5D%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20try_first_pass%0Aauth%20%20%20%20%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3E%3D%201000%20quiet_success%0Aauth%20%20%20%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20forward_pass%0Aauth%20%20%20%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_localuser.so%0Aaccount%20%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20uid%20%3C%201000%20quiet%0Aaccount%20%20%20%20%20%5Bdefault%3Dbad%20success%3Dok%20user_unknown%3Dignore%5D%20pam_sss.so%0Aaccount%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_permit.so%0A%0Apassword%20%20%20%20requisite%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_pwquality.so%20try_first_pass%20local_users_only%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%20sha512%20shadow%20try_first_pass%20use_authtok%0Apassword%20%20%20%20sufficient%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%20use_authtok%0Apassword%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_deny.so%0A%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_keyinit.so%20revoke%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_limits.so%0A-session%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_systemd.so%0Asession%20%20%20%20%20%5Bsuccess%3D1%20default%3Dignore%5D%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_succeed_if.so%20service%20in%20crond%20quiet%20use_uid%0Asession%20%20%20%20%20required%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_unix.so%0Asession%20%20%20%20%20optional%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20pam_sss.so%0A
            mode: 0644
            path: /etc/pam.d/system-auth
            overwrite: true

Group Restrict Root Logins Group contains 4 rules

[ref] Direct root logins should be allowed only for emergency use. In normal situations, the administrator should access the system via a unique unprivileged account, and then use `su` or `sudo` to execute privileged commands. Discouraging administrators from accessing the root account directly ensures an audit trail in organizations with multiple administrators. Locking down the channels through which root can connect directly also reduces opportunities for password-guessing against the root account. The `login` program uses the file `/etc/securetty` to determine which interfaces should allow root logins. The virtual devices `/dev/console` and `/dev/tty*` represent the system consoles (accessible via the Ctrl-Alt-F1 through Ctrl-Alt-F6 keyboard sequences on a default installation). The default securetty file also contains `/dev/vc/*`. These are likely to be deprecated in most environments, but may be retained for compatibility. Root should also be prohibited from connecting via network protocols. Other sections of this document include guidance describing how to prevent root from logging in via SSH.

#### Rule Verify Only Root Has UID 0 [ref]

If any account other than root has a UID of 0, this misconfiguration should be investigated and the accounts other than root should be removed or have their UID changed. If the account is associated with system commands or applications the UID should be changed to one greater than "0" but less than "1000." Otherwise assign a UID greater than "1000" that has not already been assigned.
Rationale: | An account has root authority if it has a UID of 0. Multiple accounts with a UID of 0 afford more opportunity for potential intruders to guess a password for a privileged account. Proper configuration of sudo is recommended to afford multiple system administrators access to root privileges in an accountable manner.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_no_uid_except_zero

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.10, 3.1.1, 3.1.5, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, AC-6(5), IA-4(b), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, Req-8.5, 8.2.1, SRG-OS-000480-GPOS-00227, OL07-00-020310, SV-221723r603260_rule

Remediation Shell script ⇲

    awk -F: '$3 == 0 && $1 != "root" { print $1 }' /etc/passwd | xargs --no-run-if-empty --max-lines=1 passwd -l

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Get all /etc/passwd file entries
      getent:
        database: passwd
        split: ':'
      tags:
      - DISA-STIG-OL07-00-020310
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-6(5)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-4(b)
      - PCI-DSS-Req-8.5
      - PCI-DSSv4-8.2.1
      - accounts_no_uid_except_zero
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy

    - name: Lock the password of the user accounts other than root with uid 0
      command: passwd -l {{ item.key }}
      loop: '{{ getent_passwd | dict2items | rejectattr(''key'', ''search'', ''root'')
        | list }}'
      when: item.value.1  == '0'
      tags:
      - DISA-STIG-OL07-00-020310
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-6(5)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-4(b)
      - PCI-DSS-Req-8.5
      - PCI-DSSv4-8.2.1
      - accounts_no_uid_except_zero
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy

#### Rule Direct root Logins Not Allowed [ref]

To further limit access to the `root` account, administrators can disable root logins at the console by editing the `/etc/securetty` file. This file lists all devices the root user is allowed to login to. If the file does not exist at all, the root user can login through any communication device on the system, whether via the console or via a raw network interface. This is dangerous as user can login to the system as root via Telnet, which sends the password in plain text over the network. By default, Oracle Linux 7's `/etc/securetty` file only allows the root user to login at the console physically attached to the system. To prevent root from logging in, remove the contents of this file. To prevent direct root logins, remove the contents of this file by typing the following command:

    $ sudo echo > /etc/securetty

Warning: This rule only checks the `/etc/securetty` file existence and its content. If you need to restrict user access using the `/etc/securetty` file, make sure the `pam_securetty.so` PAM module is properly enabled in relevant PAM files.

Rationale: | Disabling direct root logins ensures proper accountability and multifactor authentication to privileged accounts. Users will first login, then escalate to privileged (root) access via su / sudo. This is required for FISMA Low and FISMA Moderate systems.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_no_direct_root_logins

Identifiers and References

References: BP28(R19), 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.1, 3.1.6, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-2, CM-6(a), PR.AC-1, PR.AC-6, PR.AC-7, 8.6.1

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    echo > /etc/securetty

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Direct root Logins Not Allowed
      copy:
        dest: /etc/securetty
        content: ''
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-2
      - PCI-DSSv4-8.6.1
      - low_complexity
      - low_disruption
      - medium_severity
      - no_direct_root_logins
      - no_reboot_needed
      - restrict_strategy

#### Rule Restrict Serial Port Root Logins [ref]

To restrict root logins on serial ports, ensure lines of this form do not appear in `/etc/securetty`:

    ttyS0
    ttyS1

Rationale: | Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_restrict_serial_port_logins

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.1, 3.1.5, CCI-000770, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, CM-6(a), PR.AC-4, PR.DS-5

Remediation Shell script ⇲

    sed -i '/ttyS/d' /etc/securetty

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Restrict Serial Port Root Logins
      lineinfile:
        dest: /etc/securetty
        regexp: ttyS[0-9]
        state: absent
      tags:
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-6
      - NIST-800-53-CM-6(a)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_serial_port_logins
      - restrict_strategy

#### Rule Restrict Virtual Console Root Logins [ref]

To restrict root logins through the (deprecated) virtual console devices, ensure lines of this form do not appear in `/etc/securetty`:

    vc/1
    vc/2
    vc/3
    vc/4

Rationale: | Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_securetty_root_login_console_only

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.1, 3.1.5, CCI-000770, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, CM-6(a), PR.AC-4, PR.DS-5, 8.6.1, SRG-OS-000324-GPOS-00125

Remediation Shell script ⇲

    sed -i '/^vc\//d' /etc/securetty

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Restrict Virtual Console Root Logins
      lineinfile:
        dest: /etc/securetty
        regexp: ^vc
        state: absent
      tags:
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-6
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-8.6.1
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - securetty_root_login_console_only

Group Secure Session Configuration Files for Login Accounts Group contains 1 group and 7 rules

[ref] When a user logs into a Unix account, the system configures the user's session by reading a number of files. Many of these files are located in the user's home directory, and may have weak permissions as a result of user error or misconfiguration. If an attacker can modify or even read certain types of account configuration information, they can often gain full access to the affected user's account. Therefore, it is important to test and correct configuration file permissions for interactive accounts, particularly those of privileged users such as root or system administrators.

Group Ensure that Users Have Sensible Umask Values Group contains 4 rules

[ref] The umask setting controls the default permissions for the creation of new files. With a default `umask` setting of 077, files and directories created by users will not be readable by any other user on the system. Users who wish to make specific files group- or world-readable can accomplish this by using the chmod command. Additionally, users can make all their files readable to their group by default by setting a `umask` of 027 in their shell configuration files. If default per-user groups exist (that is, if every user has a default group whose name is the same as that user's username and whose only member is the user), then it may even be safe for users to select a `umask` of 007, making it very easy to intentionally share files with groups of which the user is a member.

#### Rule Ensure the Default Bash Umask is Set Correctly [ref]

To ensure the default umask for users of the Bash shell is set properly, add or correct the `umask` setting in `/etc/bashrc` to read as follows:

    umask 077

Rationale: | The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_umask_etc_bashrc
Identifiers and References | References: BP28(R35), 18, APO13.01, BAI03.01, BAI03.02, BAI03.03, CCI-000366, 4.3.4.3.3, A.14.1.1, A.14.2.1, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-2, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q bash; then

    var_accounts_user_umask='077'

    grep -q "^\s*umask" /etc/bashrc && \
      sed -i -E -e "s/^(\s*umask).*/\1 $var_accounts_user_umask/g" /etc/bashrc
    if ! [ $? -eq 0 ]; then
        echo "umask $var_accounts_user_umask" >> /etc/bashrc
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_bashrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_user_umask # promote to variable
      set_fact:
        var_accounts_user_umask: !!str 077
      tags:
        - always

    - name: Check if umask in /etc/bashrc is already set
      ansible.builtin.lineinfile:
        path: /etc/bashrc
        regexp: ^(\s*)umask\s+.*
        state: absent
      check_mode: true
      changed_when: false
      register: umask_replace
      when: '"bash" in ansible_facts.packages'
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_bashrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Replace user umask in /etc/bashrc
      ansible.builtin.replace:
        path: /etc/bashrc
        regexp: ^(\s*)umask(\s+).*
        replace: \g<1>umask\g<2>{{ var_accounts_user_umask }}
      when:
      - '"bash" in ansible_facts.packages'
      - umask_replace.found > 0
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_bashrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default umask is Appended Correctly
      ansible.builtin.lineinfile:
        create: true
        path: /etc/bashrc
        line: umask {{ var_accounts_user_umask }}
      when:
      - '"bash" in ansible_facts.packages'
      - umask_replace.found == 0
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_bashrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure the Default C Shell Umask is Set Correctly [ref]

To ensure the default umask for users of the C shell is set properly, add or correct the `umask` setting in `/etc/csh.cshrc` to read as follows:

    umask 077

Rationale: | The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_umask_etc_csh_cshrc
Identifiers and References | References: 18, APO13.01, BAI03.01, BAI03.02, BAI03.03, CCI-000366, 4.3.4.3.3, A.14.1.1, A.14.2.1, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-2, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    var_accounts_user_umask='077'

    grep -q "^\s*umask" /etc/csh.cshrc && \
      sed -i -E -e "s/^(\s*umask).*/\1 $var_accounts_user_umask/g" /etc/csh.cshrc
    if ! [ $? -eq 0 ]; then
        echo "umask $var_accounts_user_umask" >> /etc/csh.cshrc
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_accounts_user_umask # promote to variable
      set_fact:
        var_accounts_user_umask: !!str 077
      tags:
        - always

    - name: Check if umask in /etc/csh.cshrc is already set
      ansible.builtin.lineinfile:
        path: /etc/csh.cshrc
        regexp: ^(\s*)umask\s+.*
        state: absent
      check_mode: true
      changed_when: false
      register: umask_replace
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_csh_cshrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Replace user umask in /etc/csh.cshrc
      ansible.builtin.replace:
        path: /etc/csh.cshrc
        regexp: ^(\s*)umask(\s+).*
        replace: \g<1>umask\g<2>{{ var_accounts_user_umask }}
      when: umask_replace.found > 0
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_csh_cshrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default umask is Appended Correctly
      ansible.builtin.lineinfile:
        create: true
        path: /etc/csh.cshrc
        line: umask {{ var_accounts_user_umask }}
      when: umask_replace.found == 0
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_csh_cshrc
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure the Default Umask is Set Correctly in login.defs [ref]

To ensure the default umask controlled by `/etc/login.defs` is set properly, add or correct the `UMASK` setting in `/etc/login.defs` to read as follows:

    UMASK 077

Rationale: | The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read and written to by unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_umask_etc_login_defs

Identifiers and References

References: BP28(R35), 11, 18, 3, 9, APO13.01, BAI03.01, BAI03.02, BAI03.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.1.1, A.14.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-1, PR.IP-2, SRG-OS-000480-GPOS-00228, OL07-00-020240, SV-221718r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_user_umask='077'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^UMASK")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_user_umask"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^UMASK\\>" "/etc/login.defs"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^UMASK\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
    else
        if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/login.defs"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-020240
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_user_umask # promote to variable
      set_fact:
        var_accounts_user_umask: !!str 077
      tags:
        - always

    - name: Check if UMASK is already set
      ansible.builtin.lineinfile:
        path: /etc/login.defs
        regexp: ^(\s*)UMASK\s+.*
        state: absent
      check_mode: true
      changed_when: false
      register: result_umask_is_set
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-020240
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Replace user UMASK in /etc/login.defs
      ansible.builtin.replace:
        path: /etc/login.defs
        regexp: ^(\s*)UMASK(\s+).*
        replace: \g<1>UMASK\g<2>{{ var_accounts_user_umask }}
      when:
      - '"shadow-utils" in ansible_facts.packages'
      - result_umask_is_set.found > 0
      tags:
      - DISA-STIG-OL07-00-020240
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default UMASK is Appended Correctly
      ansible.builtin.lineinfile:
        create: true
        path: /etc/login.defs
        line: UMASK {{ var_accounts_user_umask }}
      when:
      - '"shadow-utils" in ansible_facts.packages'
      - result_umask_is_set.found == 0
      tags:
      - DISA-STIG-OL07-00-020240
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_login_defs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure the Default Umask is Set Correctly in /etc/profile [ref]

To ensure the default umask controlled by `/etc/profile` is set properly, add or correct the `umask` setting in `/etc/profile` to read as follows:

    umask 077

Note that `/etc/profile` also reads scrips within `/etc/profile.d` directory. These scripts are also valid files to set umask value. Therefore, they should also be considered during the check and properly remediated, if necessary.

Rationale: | The umask value influences the permissions assigned to files when they are created. A misconfigured umask value could result in files with excessive permissions that can be read or written to by unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_umask_etc_profile
Identifiers and References | References: BP28(R35), 18, APO13.01, BAI03.01, BAI03.02, BAI03.03, CCI-000366, 4.3.4.3.3, A.14.1.1, A.14.2.1, A.14.2.5, A.6.1.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6(1), CM-6(a), PR.IP-2, SRG-OS-000480-GPOS-00228, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    var_accounts_user_umask='077'

    readarray -t profile_files < <(find /etc/profile.d/ -type f -name '*.sh' -or -name 'sh.local')

    for file in "${profile_files[@]}" /etc/profile; do
      grep -qE '^[^#]*umask' "$file" && sed -i -E "s/^(\s*umask\s*)[0-7]+/\1$var_accounts_user_umask/g" "$file"
    done

    if ! grep -qrE '^[^#]*umask' /etc/profile*; then
      echo "umask $var_accounts_user_umask" >> /etc/profile
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_accounts_user_umask # promote to variable
      set_fact:
        var_accounts_user_umask: !!str 077
      tags:
        - always

    - name: Ensure the Default Umask is Set Correctly in /etc/profile - Locate Profile
        Configuration Files Where umask Is Defined
      ansible.builtin.find:
        paths:
        - /etc/profile.d
        patterns:
        - sh.local
        - '*.sh'
        contains: ^[\s]*umask\s+\d+
      register: result_profile_d_files
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_profile
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default Umask is Set Correctly in /etc/profile - Replace Existing
        umask Value in Files From /etc/profile.d
      ansible.builtin.replace:
        path: '{{ item.path }}'
        regexp: ^(\s*)umask\s+\d+
        replace: \1umask {{ var_accounts_user_umask }}
      loop: '{{ result_profile_d_files.files }}'
      register: result_umask_replaced_profile_d
      when: result_profile_d_files.matched
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_profile
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default Umask is Set Correctly in /etc/profile - Ensure umask Is
        Set in /etc/profile if Not Already Set Elsewhere
      ansible.builtin.lineinfile:
        create: true
        mode: 420
        path: /etc/profile
        line: umask {{ var_accounts_user_umask }}
      when: not result_profile_d_files.matched
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_profile
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure the Default Umask is Set Correctly in /etc/profile - Ensure umask Value
        For All Existing umask Definition in /etc/profile
      ansible.builtin.replace:
        path: /etc/profile
        regexp: ^(\s*)umask\s+\d+
        replace: \1umask {{ var_accounts_user_umask }}
      register: result_umask_replaced_profile
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - accounts_umask_etc_profile
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure the Logon Failure Delay is Set Correctly in login.defs [ref]

To ensure the logon failure delay controlled by `/etc/login.defs` is set properly, add or correct the `FAIL_DELAY` setting in `/etc/login.defs` to read as follows:

    FAIL_DELAY 4

Rationale: | Increasing the time between a failed authentication attempt and re-prompting to enter credentials helps to slow a single-threaded brute force attack.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_logon_fail_delay
Identifiers and References | References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00226, OL07-00-010430, SV-221693r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q shadow-utils; then

    var_accounts_fail_delay='4'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^FAIL_DELAY")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "$var_accounts_fail_delay"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^FAIL_DELAY\\>" "/etc/login.defs"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^FAIL_DELAY\\>.*/$escaped_formatted_output/gi" "/etc/login.defs"
    else
        if [[ -s "/etc/login.defs" ]] && [[ -n "$(tail -c 1 -- "/etc/login.defs" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/login.defs"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/login.defs"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-010430
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - accounts_logon_fail_delay
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy
    - name: XCCDF Value var_accounts_fail_delay # promote to variable
      set_fact:
        var_accounts_fail_delay: !!str 4
      tags:
        - always

    - name: Set accounts logon fail delay
      lineinfile:
        dest: /etc/login.defs
        regexp: ^FAIL_DELAY
        line: FAIL_DELAY {{ var_accounts_fail_delay }}
        create: true
      when: '"shadow-utils" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-010430
      - NIST-800-53-AC-7(b)
      - NIST-800-53-CM-6(a)
      - accounts_logon_fail_delay
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Limit the Number of Concurrent Login Sessions Allowed Per User [ref]

Limiting the number of allowed users and sessions per user can limit risks related to Denial of Service attacks. This addresses concurrent sessions for a single account and does not address concurrent sessions by a single user via multiple accounts. To set the number of concurrent sessions per user add the following line in `/etc/security/limits.conf` or a file under `/etc/security/limits.d/`:

    * hard maxlogins 10

Rationale: | Limiting simultaneous user logins can insulate the system from denial of service problems caused by excessive logins. Automated login processes operating improperly or maliciously may result in an exceptional number of simultaneous login sessions.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_max_concurrent_login_sessions
Identifiers and References | References: 14, 15, 18, 9, 5.5.2.2, DSS01.05, DSS05.02, CCI-000054, 4.3.3.4, SR 3.1, SR 3.8, A.13.1.1, A.13.1.3, A.13.2.1, A.14.1.2, A.14.1.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, AC-10, CM-6(a), PR.AC-5, SRG-OS-000027-GPOS-00008, OL07-00-040000, SV-221838r877399_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    var_accounts_max_concurrent_login_sessions='10'

    if grep -q '^[^#]*\<maxlogins\>' /etc/security/limits.d/*.conf; then
    	sed -i "/^[^#]*\<maxlogins\>/ s/maxlogins.*/maxlogins $var_accounts_max_concurrent_login_sessions/" /etc/security/limits.d/*.conf
    elif grep -q '^[^#]*\<maxlogins\>' /etc/security/limits.conf; then
    	sed -i "/^[^#]*\<maxlogins\>/ s/maxlogins.*/maxlogins $var_accounts_max_concurrent_login_sessions/" /etc/security/limits.conf
    else
    	echo "*	hard	maxlogins	$var_accounts_max_concurrent_login_sessions" >> /etc/security/limits.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.2.2
      - DISA-STIG-OL07-00-040000
      - NIST-800-53-AC-10
      - NIST-800-53-CM-6(a)
      - accounts_max_concurrent_login_sessions
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_accounts_max_concurrent_login_sessions # promote to variable
      set_fact:
        var_accounts_max_concurrent_login_sessions: !!str 10
      tags:
        - always

    - name: Find /etc/security/limits.d files containing maxlogins configuration
      find:
        paths: /etc/security/limits.d
        contains: ^[\s]*\*[\s]+(?:(?:hard)|(?:-))[\s]+maxlogins
        patterns: '*.conf'
      register: maxlogins
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.2.2
      - DISA-STIG-OL07-00-040000
      - NIST-800-53-AC-10
      - NIST-800-53-CM-6(a)
      - accounts_max_concurrent_login_sessions
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Limit the Number of Concurrent Login Sessions Allowed Per User in files from
        limits.d
      replace:
        dest: '{{ item.path }}'
        regexp: ^#?\*.*maxlogins.*
        replace: '*          hard    maxlogins     {{ var_accounts_max_concurrent_login_sessions
          }}'
      with_items:
      - '{{ maxlogins.files }}'
      when: '"pam" in ansible_facts.packages'
      tags:
      - CJIS-5.5.2.2
      - DISA-STIG-OL07-00-040000
      - NIST-800-53-AC-10
      - NIST-800-53-CM-6(a)
      - accounts_max_concurrent_login_sessions
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Limit the Number of Concurrent Login Sessions Allowed Per User
      lineinfile:
        state: present
        dest: /etc/security/limits.conf
        insertbefore: ^# End of file
        regexp: ^#?\*.*maxlogins
        line: '*          hard    maxlogins     {{ var_accounts_max_concurrent_login_sessions
          }}'
        create: true
      when:
      - '"pam" in ansible_facts.packages'
      - maxlogins.matched == 0
      tags:
      - CJIS-5.5.2.2
      - DISA-STIG-OL07-00-040000
      - NIST-800-53-AC-10
      - NIST-800-53-CM-6(a)
      - accounts_max_concurrent_login_sessions
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Set Interactive Session Timeout [ref]

Setting the `TMOUT` option in `/etc/profile` ensures that all user sessions will terminate based on inactivity. The value of TMOUT should be exported and read only. The `TMOUT` setting in a file loaded by `/etc/profile`or `/etc/bashrc`, e.g. `/etc/profile.d/tmout.sh` should read as follows:

    declare -xr TMOUT=600

Rationale: | Terminating an idle session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been left unattended.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_accounts_tmout

Identifiers and References

References: BP28(R29), 1, 12, 15, 16, DSS05.04, DSS05.10, DSS06.10, 3.1.11, CCI-000057, CCI-001133, CCI-002361, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-12, SC-10, AC-2(5), CM-6(a), PR.AC-7, FMT_MOF_EXT.1, 8.6.1, SRG-OS-000163-GPOS-00072, SRG-OS-000029-GPOS-00010, OL07-00-040160, SV-221841r858463_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_accounts_tmout='600'

    # if 0, no occurence of tmout found, if 1, occurence found
    tmout_found=0

    for f in /etc/profile /etc/profile.d/*.sh /etc/bashrc; do

        if grep --silent '^[^#].*TMOUT' $f; then
            sed -i -E "s/^(.*)TMOUT\s*=\s*(\w|\$)*(.*)$/declare -xr TMOUT=$var_accounts_tmout\3/g" $f
            tmout_found=1
        fi
    done

    if [ $tmout_found -eq 0 ]; then
            echo -e "\n# Set TMOUT to $var_accounts_tmout per security requirements" >> /etc/profile.d/tmout.sh
            echo "declare -xr TMOUT=$var_accounts_tmout" >> /etc/profile.d/tmout.sh
            echo "readonly TMOUT" >> /etc/profile.d/tmout.sh
            echo "export TMOUT" >> /etc/profile.d/tmout.sh
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_accounts_tmout # promote to variable
      set_fact:
        var_accounts_tmout: !!str 600
      tags:
        - always

    - name: Correct any occurrence of TMOUT in /etc/bashrc
      replace:
        path: /etc/bashrc
        regexp: ^[^#].*TMOUT=.*
        replace: declare -xr TMOUT={{ var_accounts_tmout }}
      register: bashrc_replaced
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040160
      - NIST-800-171-3.1.11
      - NIST-800-53-AC-12
      - NIST-800-53-AC-2(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-10
      - PCI-DSSv4-8.6.1
      - accounts_tmout
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Correct any occurrence of TMOUT in /etc/profile
      replace:
        path: /etc/profile
        regexp: ^[^#].*TMOUT=.*
        replace: declare -xr TMOUT={{ var_accounts_tmout }}
      register: profile_replaced
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040160
      - NIST-800-171-3.1.11
      - NIST-800-53-AC-12
      - NIST-800-53-AC-2(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-10
      - PCI-DSSv4-8.6.1
      - accounts_tmout
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set Interactive Session Timeout
      lineinfile:
        path: /etc/profile.d/tmout.sh
        create: true
        regexp: TMOUT=
        line: declare -xr TMOUT={{ var_accounts_tmout }}
        state: present
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - profile_replaced is defined and not profile_replaced.changed and bashrc_replaced
        is defined and not bashrc_replaced.changed
      tags:
      - DISA-STIG-OL07-00-040160
      - NIST-800-171-3.1.11
      - NIST-800-53-AC-12
      - NIST-800-53-AC-2(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-10
      - PCI-DSSv4-8.6.1
      - accounts_tmout
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group System Accounting with auditd Group contains 11 groups and 82 rules

[ref] The audit service provides substantial capabilities for recording system activities. By default, the service audits about SELinux AVC denials and certain types of security-relevant events such as system logins, account modifications, and authentication events performed by programs such as sudo. Under its default configuration, `auditd` has modest disk space requirements, and should not noticeably impact system performance.
NOTE: The Linux Audit daemon `auditd` can be configured to use the `augenrules` program to read audit rules files (`*.rules`) located in `/etc/audit/rules.d` location and compile them to create the resulting form of the `/etc/audit/audit.rules` configuration file during the daemon startup (default configuration). Alternatively, the `auditd` daemon can use the `auditctl` utility to read audit rules from the `/etc/audit/audit.rules` configuration file during daemon startup, and load them into the kernel. The expected behavior is configured via the appropriate `ExecStartPost` directive setting in the `/usr/lib/systemd/system/auditd.service` configuration file. To instruct the `auditd` daemon to use the `augenrules` program to read audit rules (default configuration), use the following setting:

    ExecStartPost=-/sbin/augenrules --load

in the `/usr/lib/systemd/system/auditd.service` configuration file. In order to instruct the `auditd` daemon to use the `auditctl` utility to read audit rules, use the following setting:

    ExecStartPost=-/sbin/auditctl -R /etc/audit/audit.rules

in the `/usr/lib/systemd/system/auditd.service` configuration file. Refer to `[Service]` section of the `/usr/lib/systemd/system/auditd.service` configuration file for further details.
Government networks often have substantial auditing requirements and `auditd` can be configured to meet these requirements. Examining some example audit records demonstrates how the Linux audit system satisfies common requirements. The following example from Red Hat Enterprise Linux 7 Documentation available at `https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html-single/selinux_users_and_administrators_guide/index#sect-Security-Enhanced_Linux-Fixing_Problems-Raw_Audit_Messages` shows the substantial amount of information captured in a two typical "raw" audit messages, followed by a breakdown of the most important fields. In this example the message is SELinux-related and reports an AVC denial (and the associated system call) that occurred when the Apache HTTP Server attempted to access the `/var/www/html/file1` file (labeled with the `samba_share_t` type):

    type=AVC msg=audit(1226874073.147:96): avc:  denied  { getattr } for pid=2465 comm="httpd"
    path="/var/www/html/file1" dev=dm-0 ino=284133 scontext=unconfined_u:system_r:httpd_t:s0
    tcontext=unconfined_u:object_r:samba_share_t:s0 tclass=file

    type=SYSCALL msg=audit(1226874073.147:96): arch=40000003 syscall=196 success=no exit=-13
    a0=b98df198 a1=bfec85dc a2=54dff4 a3=2008171 items=0 ppid=2463 pid=2465 auid=502 uid=48
    gid=48 euid=48 suid=48 fsuid=48 egid=48 sgid=48 fsgid=48 tty=(none) ses=6 comm="httpd"
    exe="/usr/sbin/httpd" subj=unconfined_u:system_r:httpd_t:s0 key=(null)

- `msg=audit(1226874073.147:96)`
  - The number in parentheses is the unformatted time stamp (Epoch time) for the event, which can be converted to standard time by using the `date` command.
- `{ getattr }`
  - The item in braces indicates the permission that was denied. `getattr` indicates the source process was trying to read the target file's status information. This occurs before reading files. This action is denied due to the file being accessed having the wrong label. Commonly seen permissions include `getattr`, `read`, and `write`.
- `comm="httpd"`
  - The executable that launched the process. The full path of the executable is found in the `exe=` section of the system call (`SYSCALL`) message, which in this case, is `exe="/usr/sbin/httpd"`.
- `path="/var/www/html/file1"`
  - The path to the object (target) the process attempted to access.
- `scontext="unconfined_u:system_r:httpd_t:s0"`
  - The SELinux context of the process that attempted the denied action. In this case, it is the SELinux context of the Apache HTTP Server, which is running in the `httpd_t` domain.
- `tcontext="unconfined_u:object_r:samba_share_t:s0"`
  - The SELinux context of the object (target) the process attempted to access. In this case, it is the SELinux context of `file1`. Note: the `samba_share_t` type is not accessible to processes running in the `httpd_t` domain.
- From the system call (`SYSCALL`) message, two items are of interest:
  - `success=no`: indicates whether the denial (AVC) was enforced or not. `success=no` indicates the system call was not successful (SELinux denied access). `success=yes` indicates the system call was successful - this can be seen for permissive domains or unconfined domains, such as `initrc_t` and `kernel_t`.
  - `exe="/usr/sbin/httpd"`: the full path to the executable that launched the process, which in this case, is `exe="/usr/sbin/httpd"`.

Group Configure auditd Rules for Comprehensive Auditing Group contains 8 groups and 70 rules

[ref] The `auditd` program can perform comprehensive monitoring of system activity. This section describes recommended configuration settings for comprehensive auditing, but a full description of the auditing system's capabilities is beyond the scope of this guide. The mailing list linux-audit@redhat.com exists to facilitate community discussion of the auditing system.
The audit subsystem supports extensive collection of events, including:

- Tracing of arbitrary system calls (identified by name or number) on entry or exit.
- Filtering by PID, UID, call success, system call argument (with some limitations), etc.
- Monitoring of specific files for modifications to the file's contents or metadata.

Auditing rules at startup are controlled by the file `/etc/audit/audit.rules`. Add rules to it to meet the auditing requirements for your organization. Each line in `/etc/audit/audit.rules` represents a series of arguments that can be passed to `auditctl` and can be individually tested during runtime. See documentation in `/usr/share/doc/audit-VERSION` and in the related man pages for more details.
If copying any example audit rulesets from `/usr/share/doc/audit-VERSION`, be sure to comment out the lines containing `arch=` which are not appropriate for your system's architecture. Then review and understand the following rules, ensuring rules are activated as needed for the appropriate architecture.
After reviewing all the rules, reading the following sections, and editing as needed, the new rules can be activated as follows:

    $ sudo service auditd restart

Group Record Events that Modify the System's Discretionary Access Controls Group contains 13 rules

[ref] At a minimum, the audit system should collect file permission changes for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
        -a always,exit -F arch=b32 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
        -a always,exit -F arch=b32 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:

    -a always,exit -F arch=b64 -S chmod,fchmod,fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod
        -a always,exit -F arch=b64 -S chown,fchown,fchownat,lchown -F auid>=1000 -F auid!=unset -F key=perm_mod
        -a always,exit -F arch=b64 -S setxattr,lsetxattr,fsetxattr,removexattr,lremovexattr,fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

#### Rule Record Events that Modify the System's Discretionary Access Controls - chmod [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S chmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chmod

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030410, SV-221782r810497_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="chmod"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chmod fchmod fchmodat"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit chmod tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for chmod for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of chmod in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of chmod in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for chmod for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of chmod in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of chmod in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - chown [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S chown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_chown

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030370, SV-221778r810481_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="chown"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chown fchown fchownat lchown"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit chown tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for chown for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of chown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of chown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for chown for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of chown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - chown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of chown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_chown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fchmod [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchmod -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmod

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030410, SV-221782r810497_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fchmod"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chmod fchmod fchmodat"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fchmod tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchmod for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmod in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmod in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchmod for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmod in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmod
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmod in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmod
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fchmodat [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchmodat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030410, SV-221782r810497_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fchmodat"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chmod fchmod fchmodat"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmodat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fchmodat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmodat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchmodat for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmodat
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmodat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmodat
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmodat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmodat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchmodat for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmodat
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmodat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchmodat
          syscall_grouping:
          - chmod
          - fchmod
          - fchmodat

      - name: Check existence of fchmodat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030410
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchmodat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fchown [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchown

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030370, SV-221778r810481_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fchown"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chown fchown fchownat lchown"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fchown tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchown for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchown for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fchownat [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fchownat -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fchownat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030370, SV-221778r810481_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fchownat"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chown fchown fchownat lchown"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchownat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fchownat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchownat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchownat for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchownat
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchownat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchownat
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchownat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchownat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fchownat for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchownat
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchownat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fchownat
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of fchownat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fchownat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fremovexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.
If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fremovexattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fremovexattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fremovexattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fremovexattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fremovexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fremovexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fremovexattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fremovexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fremovexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - fsetxattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_fsetxattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="fsetxattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit fsetxattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fsetxattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fsetxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fsetxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for fsetxattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fsetxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - fsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of fsetxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_fsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - lchown [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lchown -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lchown

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000466-GPOS-00210, SRG-OS-000458-GPOS-00203, SRG-OS-000474-GPOS-00219, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030370, SV-221778r810481_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="lchown"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="chown fchown fchownat lchown"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit lchown tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lchown for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of lchown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of lchown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lchown for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of lchown in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lchown
          syscall_grouping:
          - chown
          - fchown
          - fchownat
          - lchown

      - name: Check existence of lchown in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030370
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lchown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - lremovexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.
If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lremovexattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="lremovexattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit lremovexattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lremovexattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lremovexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lremovexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lremovexattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lremovexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lremovexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lremovexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lremovexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - lsetxattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_lsetxattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="lsetxattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit lsetxattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lsetxattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lsetxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lsetxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for lsetxattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lsetxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - lsetxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of lsetxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_lsetxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - removexattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root.
If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S removexattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_removexattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000458-GPOS-00203, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000474-GPOS-00219, SRG-OS-000466-GPOS-00210, SRG-OS-000064-GPOS-00033, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="removexattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_removexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit removexattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_removexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for removexattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - removexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of removexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - removexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of removexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_removexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for removexattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - removexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of removexattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - removexattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of removexattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_removexattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Discretionary Access Controls - setxattr [ref]

At a minimum, the audit system should collect file permission changes for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S setxattr -F auid>=1000 -F auid!=unset -F key=perm_mod

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | The changing of file permissions could indicate that a user is attempting to gain access to information that would otherwise be disallowed. Auditing DAC modifications can facilitate the identification of patterns of abuse among both authorized and unauthorized users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_dac_modification_setxattr

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-APP-000091-CTR-000160, SRG-APP-000492-CTR-001220, SRG-APP-000493-CTR-001225, SRG-APP-000494-CTR-001230, SRG-APP-000500-CTR-001260, SRG-APP-000507-CTR-001295, SRG-APP-000495-CTR-001235, OL07-00-030440, SV-221785r810486_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="setxattr"
    	KEY="perm_mod"
    	SYSCALL_GROUPING="fremovexattr lremovexattr removexattr fsetxattr lsetxattr setxattr"

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_setxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit setxattr tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_setxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for setxattr for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - setxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of setxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - setxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of setxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_setxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for setxattr for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - setxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of setxattr in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - setxattr
          syscall_grouping:
          - fremovexattr
          - lremovexattr
          - removexattr
          - fsetxattr
          - lsetxattr
          - setxattr

      - name: Check existence of setxattr in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030440
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_dac_modification_setxattr
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

Group Record Execution Attempts to Run SELinux Privileged Commands Group contains 4 rules
[ref] At a minimum, the audit system should collect the execution of SELinux privileged commands for all users and root.

#### Rule Record Any Attempts to Run chcon [ref]

At a minimum, the audit system should collect any execution attempt of the `chcon` command for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_execution_chcon

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030580, SV-221799r860876_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/chcon -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030580
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_chcon
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/chcon
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/chcon -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chcon -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030580
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_chcon
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Any Attempts to Run restorecon [ref]

At a minimum, the audit system should collect any execution attempt of the `restorecon` command for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F path=/usr/sbin/restorecon -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_execution_restorecon

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000392-GPOS-00172, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/restorecon -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_restorecon
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/restorecon
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/restorecon -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/restorecon
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_restorecon
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Any Attempts to Run semanage [ref]

At a minimum, the audit system should collect any execution attempt of the `semanage` command for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_execution_semanage

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, OL07-00-030560, SV-221797r860870_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/semanage -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030560
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_semanage
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/semanage
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/semanage -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/semanage -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/semanage -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030560
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_semanage
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Any Attempts to Run setsebool [ref]

At a minimum, the audit system should collect any execution attempt of the `setsebool` command for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_execution_setsebool

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, OL07-00-030570, SV-221798r860873_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/setsebool -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030570
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_setsebool
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/setsebool
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/setsebool -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/setsebool -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030570
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_execution_setsebool
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Record File Deletion Events by User Group contains 6 rules

[ref] At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

#### Rule Ensure auditd Collects File Deletion Events by User [ref]

At a minimum the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename,renameat -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir,unlink,unlinkat,rename -S renameat -F auid>=1000 -F auid!=unset -F key=delete

Warning: This rule checks for multiple syscalls related to file deletion; it was written with DISA STIG in mind. Other policies should use a separate rule for each syscall that needs to be checked. For example:

- `audit_rules_file_deletion_events_rmdir`
- `audit_rules_file_deletion_events_unlink`
- `audit_rules_file_deletion_events_unlinkat`

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000366, CCI-000172, CCI-002884, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="rmdir unlink unlinkat rename renameat"
    	KEY="delete"
    	SYSCALL_GROUPING="rmdir unlink unlinkat rename renameat"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

#### Rule Ensure auditd Collects File Deletion Events by User - rename [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rename -F auid>=1000 -F auid!=unset -F key=delete

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rename

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030910, SV-221833r853715_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="rename"
    	KEY="delete"
    	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rename
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit rename tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rename
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for rename for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rename
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rename in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rename
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rename in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rename
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for rename for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rename
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rename in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rename
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rename in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rename
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects File Deletion Events by User - renameat [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S renameat -F auid>=1000 -F auid!=unset -F key=delete

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_renameat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030910, SV-221833r853715_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="renameat"
    	KEY="delete"
    	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_renameat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit renameat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_renameat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for renameat for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - renameat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of renameat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - renameat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of renameat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_renameat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for renameat for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - renameat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of renameat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - renameat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of renameat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_renameat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects File Deletion Events by User - rmdir [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -F auid>=1000 -F auid!=unset -F key=delete

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_rmdir

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030910, SV-221833r853715_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="rmdir"
    	KEY="delete"
    	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rmdir
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit rmdir tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rmdir
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for rmdir for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rmdir
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rmdir in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rmdir
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rmdir in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rmdir
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for rmdir for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rmdir
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rmdir in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - rmdir
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of rmdir in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_rmdir
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects File Deletion Events by User - unlink [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S unlink -F auid>=1000 -F auid!=unset -F key=delete

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_unlink

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030910, SV-221833r853715_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="unlink"
    	KEY="delete"
    	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlink
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit unlink tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlink
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for unlink for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlink
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlink in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlink
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlink in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlink
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for unlink for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlink
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlink in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlink
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlink in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlink
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects File Deletion Events by User - unlinkat [ref]

At a minimum, the audit system should collect file deletion events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S unlinkat -F auid>=1000 -F auid!=unset -F key=delete

Rationale: | Auditing file deletions will create an audit trail for files that are removed from the system. The audit trail could aid in system troubleshooting, as well as, detecting malicious processes that attempt to delete log files to conceal their presence.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_file_deletion_events_unlinkat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-000366, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.4, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.1.1, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.MA-2, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-OS-000467-GPOS-00211, SRG-OS-000468-GPOS-00212, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030910, SV-221833r853715_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="unlinkat"
    	KEY="delete"
    	SYSCALL_GROUPING="unlink unlinkat rename renameat rmdir"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlinkat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit unlinkat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlinkat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for unlinkat for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlinkat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlinkat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlinkat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlinkat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlinkat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for unlinkat for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlinkat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlinkat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/delete.rules
        set_fact: audit_file="/etc/audit/rules.d/delete.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - unlinkat
          syscall_grouping:
          - unlink
          - unlinkat
          - rename
          - renameat
          - rmdir

      - name: Check existence of unlinkat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=delete
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030910
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_file_deletion_events_unlinkat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

Group Record Unauthorized Access Attempts Events to Files (unsuccessful) Group contains 6 rules

[ref] At a minimum, the audit system should collect unauthorized file accesses for all users and root. Note that the "-F arch=b32" lines should be present even on a 64 bit system. These commands identify system calls for auditing. Even if the system is 64 bit it can still execute 32 bit system calls. Additionally, these rules can be configured in a number of ways while still achieving the desired effect. An example of this is that the "-S" calls could be split up and placed on separate lines, however, this is less efficient. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
        -a always,exit -F arch=b32 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If your system is 64 bit then these lines should be duplicated and the arch=b32 replaced with arch=b64 as follows:

    -a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
        -a always,exit -F arch=b64 -S creat,open,openat,open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

#### Rule Record Unsuccessful Access Attempts to Files - creat [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S creat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S creat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_creat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="creat"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit creat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for creat EACCES for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for creat EACCES for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for creat EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for creat EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - creat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of creat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_creat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Unsuccessful Access Attempts to Files - ftruncate [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_ftruncate

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="ftruncate"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit ftruncate tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for ftruncate EACCES for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for ftruncate EACCES for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for ftruncate EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for ftruncate EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - ftruncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of ftruncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_ftruncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Unsuccessful Access Attempts to Files - open [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S open -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S open -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ! ( grep -q aarch64 /proc/sys/kernel/osrelease ); }; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="open"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit open tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open EACCES for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open EACCES for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - not ( ansible_architecture == "aarch64" )
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Unsuccessful Access Attempts to Files - open_by_handle_at [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S open_by_handle_at -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S open_by_handle_at,truncate,ftruncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_open_by_handle_at

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="open_by_handle_at"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit open_by_handle_at tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open_by_handle_at EACCES for 32bit
        platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open_by_handle_at EACCES for 64bit
        platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open_by_handle_at EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for open_by_handle_at EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - open_by_handle_at
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of open_by_handle_at in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_open_by_handle_at
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Unsuccessful Access Attempts to Files - openat [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S openat -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S openat -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_openat

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="openat"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit openat tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for openat EACCES for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for openat EACCES for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for openat EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for openat EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - openat
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of openat in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_openat
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Unsuccessful Access Attempts to Files - truncate [ref]

At a minimum, the audit system should collect unauthorized file accesses for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b32 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

If the system is 64 bit then also add the following lines:

    -a always,exit -F arch=b64 -S truncate -F exit=-EACCES -F auid>=1000 -F auid!=unset -F key=access
    -a always,exit -F arch=b64 -S truncate -F exit=-EPERM -F auid>=1000 -F auid!=unset -F key=access

Warning: Note that these rules can be configured in a number of ways while still achieving the desired effect. Here the system calls have been placed independent of other system calls. Grouping these system calls with others as identifying earlier in this guide is more efficient.

Rationale: | Unsuccessful attempts to access files could be an indicator of malicious activity on a system. Auditing these events could serve as evidence of potential system compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_unsuccessful_file_modification_truncate

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.4, Req-10.2.1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000064-GPOS-00033, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-APP-000495-CTR-001235, OL07-00-030510, SV-221792r853694_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL="truncate"
    KEY="access"
    SYSCALL_GROUPING="creat ftruncate truncate open openat open_by_handle_at"

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EACCES"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F exit=-EPERM"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit truncate tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for truncate EACCES for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for truncate EACCES for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EACCES -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EACCES -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EACCES
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for truncate EPERM for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for truncate EPERM for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/access.rules
        set_fact: audit_file="/etc/audit/rules.d/access.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - truncate
          syscall_grouping:
          - creat
          - ftruncate
          - truncate
          - open
          - openat
          - open_by_handle_at

      - name: Check existence of truncate in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F exit=-EPERM -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F exit=-EPERM -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F exit=-EPERM
            -F auid>=1000 -F auid!=unset -F key=access
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030510
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.1
      - PCI-DSS-Req-10.2.4
      - audit_rules_unsuccessful_file_modification_truncate
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

Group Record Information on Kernel Modules Loading and Unloading Group contains 2 rules

[ref] To capture kernel module loading and unloading events, use following lines, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

    -a always,exit -F arch=ARCH -S init_module,delete_module -F key=modules

Place to add the lines depends on a way `auditd` daemon is configured. If it is configured to use the `augenrules` program (the default), add the lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`. If the `auditd` daemon is configured to use the `auditctl` utility, add the lines to file `/etc/audit/audit.rules`.

#### Rule Ensure auditd Collects Information on Kernel Module Unloading - delete_module [ref]

To capture kernel module unloading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

    -a always,exit -F arch=ARCH -S delete_module -F auid>=1000 -F auid!=unset -F key=modules

Place to add the line depends on a way `auditd` daemon is configured. If it is configured to use the `augenrules` program (the default), add the line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`. If the `auditd` daemon is configured to use the `auditctl` utility, add the line to file `/etc/audit/audit.rules`.

Rationale: | The removal of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_delete

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-APP-000495-CTR-001235, SRG-APP-000504-CTR-001280, OL07-00-030830, SV-221823r833103_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    # Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
    #       it's required on a 64-bit system to check also for the presence
    #       of 32-bit's equivalent of the corresponding rule.
    #       (See `man 7 audit.rules` for details )
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""

    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"

    	SYSCALL="delete_module"
    	KEY="modules"
    	SYSCALL_GROUPING="delete_module"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030830
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_delete
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Set architecture for audit delete_module tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030830
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_delete
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Perform remediation of Audit rules for delete_module for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - delete_module
          syscall_grouping: []

      - name: Check existence of delete_module in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
        set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - delete_module
          syscall_grouping: []

      - name: Check existence of delete_module in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030830
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_delete
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Perform remediation of Audit rules for delete_module for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - delete_module
          syscall_grouping: []

      - name: Check existence of delete_module in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
        set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - delete_module
          syscall_grouping: []

      - name: Check existence of delete_module in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030830
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_delete
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Ensure auditd Collects Information on Kernel Module Loading - init_module [ref]

To capture kernel module loading events, use following line, setting ARCH to either b32 for 32-bit system, or having two lines for both b32 and b64 in case your system is 64-bit:

    -a always,exit -F arch=ARCH -S init_module -F auid>=1000 -F auid!=unset -F key=modules

Place to add the line depends on a way `auditd` daemon is configured. If it is configured to use the `augenrules` program (the default), add the line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`. If the `auditd` daemon is configured to use the `auditctl` utility, add the line to file `/etc/audit/audit.rules`.

Rationale: | The addition of kernel modules can be used to alter the behavior of the kernel and potentially introduce malicious code into kernel space. It is important to have an audit trail of modules that have been introduced into the kernel.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_kernel_module_loading_init

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000477-GPOS-00222, SRG-APP-000495-CTR-001235, SRG-APP-000504-CTR-001280, OL07-00-030820, SV-221821r833100_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    # Note: 32-bit and 64-bit kernel syscall numbers not always line up =>
    #       it's required on a 64-bit system to check also for the presence
    #       of 32-bit's equivalent of the corresponding rule.
    #       (See `man 7 audit.rules` for details )
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""

    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"

    	SYSCALL="init_module"
    	KEY="modules"
    	SYSCALL_GROUPING="init_module finit_module"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030820
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_init
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Set architecture for audit init_module tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - DISA-STIG-OL07-00-030820
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_init
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Perform remediation of Audit rules for init_module for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - init_module
          syscall_grouping:
          - init_module
          - finit_module

      - name: Check existence of init_module in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
        set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - init_module
          syscall_grouping:
          - init_module
          - finit_module

      - name: Check existence of init_module in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030820
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_init
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Perform remediation of Audit rules for init_module for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - init_module
          syscall_grouping:
          - init_module
          - finit_module

      - name: Check existence of init_module in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/module-change.rules
        set_fact: audit_file="/etc/audit/rules.d/module-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - init_module
          syscall_grouping:
          - init_module
          - finit_module

      - name: Check existence of init_module in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=module-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - DISA-STIG-OL07-00-030820
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - audit_rules_kernel_module_loading_init
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

Group Record Attempts to Alter Logon and Logout Events Group contains 3 rules

[ref] The audit system already collects login information for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to watch for attempted manual edits of files involved in storing logon events:

    -w /var/log/tallylog -p wa -k logins
    -w /var/log/faillock -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file in order to watch for unattempted manual edits of files involved in storing logon events:

    -w /var/log/tallylog -p wa -k logins
    -w /var/log/faillock -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

#### Rule Record Attempts to Alter Logon and Logout Events - faillock [ref]

The audit system already collects login information for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to watch for attempted manual edits of files involved in storing logon events:

    -w /var/log/faillock -p wa -k logins

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file in order to watch for unattempted manual edits of files involved in storing logon events:

    -w /var/log/faillock -p wa -k logins

Rationale: | Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_login_events_faillock

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290, OL07-00-030610, SV-221801r853707_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    var_accounts_passwords_pam_faillock_dir='/var/log/faillock'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/logins.rules"
        # If the logins.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+${var_accounts_passwords_pam_faillock_dir}" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir} $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+${var_accounts_passwords_pam_faillock_dir}$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w ${var_accounts_passwords_pam_faillock_dir} -p wa -k logins" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy
    - name: XCCDF Value var_accounts_passwords_pam_faillock_dir # promote to variable
      set_fact:
        var_accounts_passwords_pam_faillock_dir: !!str /var/log/faillock
      tags:
        - always

    - name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
        exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key logins
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)logins$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/logins.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for {{ var_accounts_passwords_pam_faillock_dir }} already
        exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+{{ var_accounts_passwords_pam_faillock_dir }}\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for {{ var_accounts_passwords_pam_faillock_dir }} in /etc/audit/audit.rules
      lineinfile:
        line: -w {{ var_accounts_passwords_pam_faillock_dir }} -p wa -k logins
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030610
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_faillock
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Attempts to Alter Logon and Logout Events - lastlog [ref]

The audit system already collects login information for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to watch for attempted manual edits of files involved in storing logon events:

    -w /var/log/lastlog -p wa -k logins

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file in order to watch for unattempted manual edits of files involved in storing logon events:

    -w /var/log/lastlog -p wa -k logins

Rationale: | Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_login_events_lastlog

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000470-GPOS-00214, SRG-APP-000495-CTR-001235, SRG-APP-000503-CTR-001275, SRG-APP-000506-CTR-001290, OL07-00-030620, SV-221802r853708_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/lastlog" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/logins.rules"
        # If the logins.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/lastlog" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/lastlog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/lastlog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/lastlog -p wa -k logins" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key logins
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)logins$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/logins.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/lastlog in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /var/log/lastlog -p wa -k logins
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/lastlog already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/var/log/lastlog\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/lastlog in /etc/audit/audit.rules
      lineinfile:
        line: -w /var/log/lastlog -p wa -k logins
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - DISA-STIG-OL07-00-030620
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_lastlog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Attempts to Alter Logon and Logout Events - tallylog [ref]

The audit system already collects login information for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to watch for attempted manual edits of files involved in storing logon events:

    -w /var/log/tallylog -p wa -k logins

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file in order to watch for unattempted manual edits of files involved in storing logon events:

    -w /var/log/tallylog -p wa -k logins

Rationale: | Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_login_events_tallylog

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000172, CCI-002884, CCI-000126, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-OS-000392-GPOS-00172, SRG-OS-000470-GPOS-00214, SRG-OS-000473-GPOS-00218, SRG-APP-000503-CTR-001275

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/logins.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/tallylog" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/logins.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/logins.rules"
        # If the logins.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/tallylog" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/tallylog $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/tallylog$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/tallylog -p wa -k logins" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key logins
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)logins$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/logins.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/logins.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/tallylog in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /var/log/tallylog -p wa -k logins
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/tallylog already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/var/log/tallylog\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/tallylog in /etc/audit/audit.rules
      lineinfile:
        line: -w /var/log/tallylog -p wa -k logins
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_login_events_tallylog
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

Group Record Information on the Use of Privileged Commands Group contains 17 rules
[ref] At a minimum, the audit system should collect the execution of privileged commands for all users and root.

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands [ref]

The audit system should collect information about usage of privileged commands for all users. These are commands with suid or sgid bits on and they are specially risky in local block device partitions not mounted with noexec and nosuid options. Therefore, these partitions should be first identified by the following command:

    findmnt -n -l -k -it $(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,) | grep -Pv "noexec|nosuid"

For all partitions listed by the previous command, it is necessary to search for setuid / setgid programs using the following command:

    $ sudo find PARTITION -xdev -perm /6000 -type f 2>/dev/null

For each setuid / setgid program identified by the previous command, an audit rule must be present in the appropriate place using the following line structure:

    -a always,exit -F path=PROG_PATH -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup, add the line to a file with suffix `.rules` in the `/etc/audit/rules.d` directory, replacing the PROG_PATH part with the full path of that setuid / setgid identified program. If the `auditd` daemon is configured to use the `auditctl` utility instead, add the line to the `/etc/audit/audit.rules` file, also replacing the PROG_PATH part with the full path of that setuid / setgid identified program.
Warning: This rule checks for multiple syscalls related to privileged commands. If needed to check specific privileged commands, other more specific rules should be considered. For example:

- `audit_rules_privileged_commands_su`
- `audit_rules_privileged_commands_umount`
- `audit_rules_privileged_commands_passwd`

Warning: Note that OVAL check and Bash / Ansible remediation of this rule explicitly excludes file systems mounted at

    /proc

directory and its subdirectories. It is a virtual file system and it doesn't contain executable applications. At the same time, interacting with this file system during check or remediation caused undesirable errors.

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern that can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO08.04, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.05, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-002234, 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.5, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.3.4.5.9, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 3.9, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.1, A.16.1.2, A.16.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.3, A.6.2.1, A.6.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-2, DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, DE.DP-4, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, RS.CO-2, Req-10.2.2, SRG-OS-000327-GPOS-00127

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""

    FILTER_NODEV=$(awk '/nodev/ { print $2 }' /proc/filesystems | paste -sd,)
    PARTITIONS=$(findmnt -n -l -k -it $FILTER_NODEV | grep -Pv "noexec|nosuid|/proc($|/.*$)" | awk '{ print $1 }')
    for PARTITION in $PARTITIONS; do
      PRIV_CMDS=$(find "${PARTITION}" -xdev -perm /6000 -type f 2>/dev/null)
      for PRIV_CMD in $PRIV_CMDS; do
        OTHER_FILTERS="-F path=$PRIV_CMD -F perm=x"
        # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'augenrules', then check if the audit rule is defined
        # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
        # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
        default_file="/etc/audit/rules.d/$KEY.rules"
        # As other_filters may include paths, lets use a different delimiter for it
        # The "F" script expression tells sed to print the filenames where the expressions matched
        readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
            file_to_inspect="/etc/audit/rules.d/$KEY.rules"
            files_to_inspect=("$file_to_inspect")
            if [ ! -e "$file_to_inspect" ]
            then
                touch "$file_to_inspect"
                chmod 0640 "$file_to_inspect"
            fi
        fi

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
        # file to the list of files to be inspected
        default_file="/etc/audit/audit.rules"
        files_to_inspect+=('/etc/audit/audit.rules' )

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
      done
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - audit_rules_privileged_commands
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure auditd Collects Information on the Use of Privileged Commands - Set
        List of Mount Points Which Permits Execution of Privileged Commands
      ansible.builtin.set_fact:
        privileged_mount_points: '{{(ansible_facts.mounts | rejectattr(''options'', ''search'',
          ''noexec|nosuid'') | rejectattr(''mount'', ''match'', ''/proc($|/.*$)'') | map(attribute=''mount'')
          | list ) }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - audit_rules_privileged_commands
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure auditd Collects Information on the Use of Privileged Commands - Search
        for Privileged Commands in Eligible Mount Points
      ansible.builtin.shell:
        cmd: find {{ item }} -xdev -perm /6000 -type f 2>/dev/null
      register: result_privileged_commands_search
      changed_when: false
      failed_when: false
      with_items: '{{ privileged_mount_points }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - audit_rules_privileged_commands
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure auditd Collects Information on the Use of Privileged Commands - Set
        List of Privileged Commands Found in Eligible Mount Points
      ansible.builtin.set_fact:
        privileged_commands: '{{( result_privileged_commands_search.results | map(attribute=''stdout_lines'')
          | select() | list ) | sum(start=[]) }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - audit_rules_privileged_commands
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure auditd Collects Information on the Use of Privileged Commands - Privileged
        Commands are Present in the System
      block:

      - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
          Rules for All Privileged Commands in augenrules Format
        ansible.builtin.lineinfile:
          path: /etc/audit/rules.d/privileged.rules
          line: -a always,exit -F path={{ item }} -F perm=x -F auid>=1000 -F auid!=unset
            -F key=privileged
          regexp: ^.*path={{ item | regex_escape() }} .*$
          create: true
        with_items:
        - '{{ privileged_commands }}'

      - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
          Rules for All Privileged Commands in auditctl Format
        ansible.builtin.lineinfile:
          path: /etc/audit/audit.rules
          line: -a always,exit -F path={{ item }} -F perm=x -F auid>=1000 -F auid!=unset
            -F key=privileged
          regexp: ^.*path={{ item | regex_escape() }} .*$
          create: true
        with_items:
        - '{{ privileged_commands }}'

      - name: Ensure auditd Collects Information on the Use of Privileged Commands - Search
          for Duplicated Rules in Other Files
        ansible.builtin.find:
          paths: /etc/audit/rules.d
          recurse: false
          contains: ^-a always,exit -F path={{ item }} .*$
          patterns: '*.rules'
        with_items:
        - '{{ privileged_commands }}'
        register: result_augenrules_files

      - name: Ensure auditd Collects Information on the Use of Privileged Commands - Ensure
          Rules for Privileged Commands are Defined Only in One File
        ansible.builtin.lineinfile:
          path: '{{ item.1.path }}'
          regexp: ^-a always,exit -F path={{ item.0.item }} .*$
          state: absent
        with_subelements:
        - '{{ result_augenrules_files.results }}'
        - files
        when:
        - item.1.path != '/etc/audit/rules.d/privileged.rules'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - privileged_commands is defined
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - audit_rules_privileged_commands
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - chage [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chage

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000468-GPOS-00212, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000501-CTR-001265, SRG-APP-000502-CTR-001270, OL07-00-030660, SV-221806r833058_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/chage -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030660
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_chage
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/chage
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chage -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/chage -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chage -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030660
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_chage
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - chsh [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_chsh

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030720, SV-221812r833073_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/chsh -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030720
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_chsh
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/chsh
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/chsh -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/chsh -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/chsh -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030720
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_chsh
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - crontab [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_crontab

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030800, SV-221818r833091_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/crontab -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030800
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_crontab
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/crontab
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/crontab -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/crontab -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/crontab -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030800
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_crontab
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - gpasswd [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_gpasswd

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030650, SV-221805r833055_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/gpasswd -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030650
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_gpasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/gpasswd
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/gpasswd -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/gpasswd -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030650
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_gpasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - newgrp [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_newgrp

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030710, SV-221811r833070_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/newgrp -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030710
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_newgrp
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/newgrp
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/newgrp -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/newgrp -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/newgrp -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030710
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_newgrp
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - pam_timestamp_check [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/pam_timestamp_check
    -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/sbin/pam_timestamp_check
    -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_pam_timestamp_check

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030810, SV-221819r833094_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/pam_timestamp_check -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030810
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_pam_timestamp_check
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/pam_timestamp_check
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset
            (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/pam_timestamp_check
            -F perm=x -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/pam_timestamp_check
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000 -F auid!=unset
            (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/pam_timestamp_check -F perm=x -F auid>=1000
            -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/pam_timestamp_check
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030810
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_pam_timestamp_check
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - passwd [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_passwd

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030630, SV-221803r833049_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/passwd -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030630
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/passwd
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/passwd -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/passwd -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/passwd -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030630
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - postdrop [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postdrop

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030760, SV-221815r833082_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/postdrop -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030760
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_postdrop
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/postdrop
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/postdrop -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postdrop -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/postdrop -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postdrop -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030760
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_postdrop
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - postqueue [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_postqueue

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030770, SV-221816r833085_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/postqueue -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030770
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_postqueue
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/postqueue
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/postqueue -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postqueue -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/postqueue -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/postqueue -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030770
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_postqueue
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - ssh-keysign [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_ssh_keysign

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030780, SV-221817r833088_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/libexec/openssh/ssh-keysign -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030780
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_ssh_keysign
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/libexec/openssh/ssh-keysign
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset
            (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/libexec/openssh/ssh-keysign
            -F perm=x -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/libexec/openssh/ssh-keysign
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000 -F auid!=unset
            (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/libexec/openssh/ssh-keysign -F perm=x -F auid>=1000
            -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/libexec/openssh/ssh-keysign
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030780
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_ssh_keysign
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - su [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_su

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000064-GPOS-0003, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030680, SV-221808r833064_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/su -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030680
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_su
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/su
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/su -F perm=x -F auid>=1000
            -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/su -F perm=x -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/su -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030680
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_su
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - sudo [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudo

Identifiers and References

References: BP28(R19), 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000466-GPOS-00210, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, OL07-00-030690, SV-221809r833067_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/sudo -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030690
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_sudo
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/sudo
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudo -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/sudo -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudo -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030690
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_sudo
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - sudoedit [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/sudoedit -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_sudoedit

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/sudoedit -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_sudoedit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/sudoedit
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/sudoedit -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/sudoedit -F
            perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_sudoedit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - umount [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_umount

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000169, CCI-000135, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, OL07-00-030750, SV-221814r833079_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/bin/umount -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030750
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_umount
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/bin/umount
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/bin/umount -F perm=x -F
            auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/umount -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/bin/umount -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/bin/umount -F perm=x
            -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030750
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_umount
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - unix_chkpwd [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_unix_chkpwd

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R6.5, AC-2(4), AU-2(d), AU-3, AU-3.1, AU-12(a), AU-12(c), AU-12.1(ii), AU-12.1(iv), AC-6(9), CM-6(a), MA-4(1)(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000029-CTR-000085, SRG-APP-000495-CTR-001235, OL07-00-030640, SV-221804r833052_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/unix_chkpwd -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030640
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(a)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-12.1(ii)
      - NIST-800-53-AU-12.1(iv)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-AU-3
      - NIST-800-53-AU-3.1
      - NIST-800-53-CM-6(a)
      - NIST-800-53-MA-4(1)(a)
      - audit_rules_privileged_commands_unix_chkpwd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/unix_chkpwd
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/unix_chkpwd -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/unix_chkpwd
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/unix_chkpwd -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/unix_chkpwd
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030640
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(a)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-12.1(ii)
      - NIST-800-53-AU-12.1(iv)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-AU-3
      - NIST-800-53-AU-3.1
      - NIST-800-53-CM-6(a)
      - NIST-800-53-MA-4(1)(a)
      - audit_rules_privileged_commands_unix_chkpwd
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure auditd Collects Information on the Use of Privileged Commands - userhelper [ref]

At a minimum, the audit system should collect the execution of privileged commands for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add a line of the following form to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add a line of the following form to `/etc/audit/audit.rules`:

    -a always,exit -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged

Rationale:

Misuse of privileged functions, either intentionally or unintentionally by authorized users, or by unauthorized external entities that have compromised system accounts, is a serious and ongoing concern and can have significant adverse impacts on organizations. Auditing the use of privileged functions is one way to detect such misuse and identify the risk from insider and advanced persistent threats.
Privileged programs are subject to escalation-of-privilege attacks, which attempt to subvert their normal role of providing some necessary but limited capability. As such, motivation exists to monitor these programs for unusual activity.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_privileged_commands_userhelper

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030670, SV-221807r833061_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    ACTION_ARCH_FILTERS="-a always,exit"
    OTHER_FILTERS="-F path=/usr/sbin/userhelper -F perm=x"
    AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    SYSCALL=""
    KEY="privileged"
    SYSCALL_GROUPING=""
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030670
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_userhelper
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for /usr/sbin/userhelper
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/privileged.rules
        set_fact: audit_file="/etc/audit/rules.d/privileged.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F path=/usr/sbin/userhelper -F perm=x
            -F auid>=1000 -F auid!=unset (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/userhelper
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls: []
          syscall_grouping: []

      - name: Check existence of  in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit(( -S |,)\w+)*(( -S |,){{ item }})+(( -S |,)\w+)* -F
            path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit)(?=.*(?:(?:-S |,)(?:{{ syscalls_found | join("|") }}))\b)((?:(
            -S |,)\w+)+)( -F path=/usr/sbin/userhelper -F perm=x -F auid>=1000 -F auid!=unset
            (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit{{ syscalls | join(',') }} -F path=/usr/sbin/userhelper
            -F perm=x -F auid>=1000 -F auid!=unset -F key=privileged
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030670
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - audit_rules_privileged_commands_userhelper
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Records Events that Modify Date and Time Information Group contains 5 rules
[ref] Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time. All changes to the system time should be audited.

#### Rule Record attempts to alter time through adjtimex [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S adjtimex -F key=audit_time_rules

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S adjtimex -F key=audit_time_rules

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:

    -a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale: | Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_time_adjtimex

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
            # so append it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday stime"
            SYSCALL_GROUPING="adjtimex settimeofday stime"
        elif [ ${ARCH} = "b64" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
            # therefore don't add it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday"
            SYSCALL_GROUPING="adjtimex settimeofday"
        fi
        OTHER_FILTERS=""
        AUID_FILTERS=""
        KEY="audit_time_rules"
        # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'augenrules', then check if the audit rule is defined
        # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
        # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
        default_file="/etc/audit/rules.d/$KEY.rules"
        # As other_filters may include paths, lets use a different delimiter for it
        # The "F" script expression tells sed to print the filenames where the expressions matched
        readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
            file_to_inspect="/etc/audit/rules.d/$KEY.rules"
            files_to_inspect=("$file_to_inspect")
            if [ ! -e "$file_to_inspect" ]
            then
                touch "$file_to_inspect"
                chmod 0640 "$file_to_inspect"
            fi
        fi

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
        # file to the list of files to be inspected
        default_file="/etc/audit/audit.rules"
        files_to_inspect+=('/etc/audit/audit.rules' )

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_adjtimex
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set architecture for audit tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_adjtimex
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for adjtimex for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - adjtimex
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of adjtimex in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - adjtimex
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of adjtimex in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_adjtimex
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for adjtimex for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - adjtimex
          syscall_grouping:
          - adjtimex
          - settimeofday

      - name: Check existence of adjtimex in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - adjtimex
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of adjtimex in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_adjtimex
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Attempts to Alter Time Through clock_settime [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S clock_settime -F a0=0x0 -F key=time-change

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:

    -a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale: | Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_time_clock_settime

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS="-F a0=0x0"
    	AUID_FILTERS=""
    	SYSCALL="clock_settime"
    	KEY="time-change"
    	SYSCALL_GROUPING=""
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_clock_settime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set architecture for audit tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_clock_settime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for clock_settime for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - clock_settime
          syscall_grouping: []

      - name: Check existence of clock_settime in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
        set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
            key=time-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - clock_settime
          syscall_grouping: []

      - name: Check existence of clock_settime in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F a0=0x0 -F
            key=time-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_clock_settime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for clock_settime for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - clock_settime
          syscall_grouping: []

      - name: Check existence of clock_settime in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/time-change.rules
        set_fact: audit_file="/etc/audit/rules.d/time-change.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
            key=time-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - clock_settime
          syscall_grouping: []

      - name: Check existence of clock_settime in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F a0=0x0 (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F a0=0x0 (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F a0=0x0 -F
            key=time-change
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_clock_settime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record attempts to alter time through settimeofday [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -a always,exit -F arch=b32 -S settimeofday -F key=audit_time_rules

If the system is 64 bit then also add the following line:

    -a always,exit -F arch=b64 -S settimeofday -F key=audit_time_rules

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined syscalls:

    -a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale: | Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_time_settimeofday

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
            # so append it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday stime"
            SYSCALL_GROUPING="adjtimex settimeofday stime"
        elif [ ${ARCH} = "b64" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
            # therefore don't add it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday"
            SYSCALL_GROUPING="adjtimex settimeofday"
        fi
        OTHER_FILTERS=""
        AUID_FILTERS=""
        KEY="audit_time_rules"
        # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'augenrules', then check if the audit rule is defined
        # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
        # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
        default_file="/etc/audit/rules.d/$KEY.rules"
        # As other_filters may include paths, lets use a different delimiter for it
        # The "F" script expression tells sed to print the filenames where the expressions matched
        readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
            file_to_inspect="/etc/audit/rules.d/$KEY.rules"
            files_to_inspect=("$file_to_inspect")
            if [ ! -e "$file_to_inspect" ]
            then
                touch "$file_to_inspect"
                chmod 0640 "$file_to_inspect"
            fi
        fi

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
        # file to the list of files to be inspected
        default_file="/etc/audit/audit.rules"
        files_to_inspect+=('/etc/audit/audit.rules' )

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_settimeofday
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set architecture for audit tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_settimeofday
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for settimeofday for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - settimeofday
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of settimeofday in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - settimeofday
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of settimeofday in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_settimeofday
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for settimeofday for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - settimeofday
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of settimeofday in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - settimeofday
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of settimeofday in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_settimeofday
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Attempts to Alter Time Through stime [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d` for both 32 bit and 64 bit systems:

    -a always,exit -F arch=b32 -S stime -F key=audit_time_rules

Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file for both 32 bit and 64 bit systems:

    -a always,exit -F arch=b32 -S stime -F key=audit_time_rules

Since the 64 bit version of the "stime" system call is not defined in the audit lookup table, the corresponding "-F arch=b64" form of this rule is not expected to be defined on 64 bit systems (the aforementioned "-F arch=b32" stime rule form itself is sufficient for both 32 bit and 64 bit systems). The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport. Multiple system calls can be defined on the same line to save space if desired, but is not required. See an example of multiple combined system calls:

    -a always,exit -F arch=b64 -S adjtimex,settimeofday -F key=audit_time_rules

Rationale: | Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_time_stime

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit && { ( ! ( grep -q aarch64 /proc/sys/kernel/osrelease ) && ! ( grep -q s390x /proc/sys/kernel/osrelease ) ); }; then

    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
        # Create expected audit group and audit rule form for particular system call & architecture
        if [ ${ARCH} = "b32" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call is known at 32-bit arch (see e.g "$ ausyscall i386 stime" 's output)
            # so append it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday stime"
            SYSCALL_GROUPING="adjtimex settimeofday stime"
        elif [ ${ARCH} = "b64" ]
        then
            ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
            # stime system call isn't known at 64-bit arch (see "$ ausyscall x86_64 stime" 's output)
            # therefore don't add it to the list of time group system calls to be audited
            SYSCALL="adjtimex settimeofday"
            SYSCALL_GROUPING="adjtimex settimeofday"
        fi
        OTHER_FILTERS=""
        AUID_FILTERS=""
        KEY="audit_time_rules"
        # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'augenrules', then check if the audit rule is defined
        # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
        # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
        default_file="/etc/audit/rules.d/$KEY.rules"
        # As other_filters may include paths, lets use a different delimiter for it
        # The "F" script expression tells sed to print the filenames where the expressions matched
        readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
        # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
        if [ ${#files_to_inspect[@]} -eq "0" ]
        then
            file_to_inspect="/etc/audit/rules.d/$KEY.rules"
            files_to_inspect=("$file_to_inspect")
            if [ ! -e "$file_to_inspect" ]
            then
                touch "$file_to_inspect"
                chmod 0640 "$file_to_inspect"
            fi
        fi

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
        unset syscall_a
        unset syscall_grouping
        unset syscall_string
        unset syscall
        unset file_to_edit
        unset rule_to_edit
        unset rule_syscalls_to_edit
        unset other_string
        unset auid_string
        unset full_rule

        # Load macro arguments into arrays
        read -a syscall_a <<< $SYSCALL
        read -a syscall_grouping <<< $SYSCALL_GROUPING

        # Create a list of audit *.rules files that should be inspected for presence and correctness
        # of a particular audit rule. The scheme is as follows:
        #
        # -----------------------------------------------------------------------------------------
        #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
        # -----------------------------------------------------------------------------------------
        #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
        # -----------------------------------------------------------------------------------------
        #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
        #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
        # -----------------------------------------------------------------------------------------
        #
        files_to_inspect=()

        # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
        # file to the list of files to be inspected
        default_file="/etc/audit/audit.rules"
        files_to_inspect+=('/etc/audit/audit.rules' )

        # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
        skip=1

        for audit_file in "${files_to_inspect[@]}"
        do
            # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
            # i.e, collect rules that match:
            # * the action, list and arch, (2-nd argument)
            # * the other filters, (3-rd argument)
            # * the auid filters, (4-rd argument)
            readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

            candidate_rules=()
            # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
            for s_rule in "${similar_rules[@]}"
            do
                # Strip all the options and fields we know of,
                # than check if there was any field left over
                extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
                grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
            done

            if [[ ${#syscall_a[@]} -ge 1 ]]
            then
                # Check if the syscall we want is present in any of the similar existing rules
                for rule in "${candidate_rules[@]}"
                do
                    rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                    all_syscalls_found=0
                    for syscall in "${syscall_a[@]}"
                    do
                        grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                           # A syscall was not found in the candidate rule
                           all_syscalls_found=1
                           }
                    done
                    if [[ $all_syscalls_found -eq 0 ]]
                    then
                        # We found a rule with all the syscall(s) we want; skip rest of macro
                        skip=0
                        break
                    fi

                    # Check if this rule can be grouped with our target syscall and keep track of it
                    for syscall_g in "${syscall_grouping[@]}"
                    do
                        if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                        then
                            file_to_edit=${audit_file}
                            rule_to_edit=${rule}
                            rule_syscalls_to_edit=${rule_syscalls}
                        fi
                    done
                done
            else
                # If there is any candidate rule, it is compliant; skip rest of macro
                if [ "${#candidate_rules[@]}" -gt 0 ]
                then
                    skip=0
                fi
            fi

            if [ "$skip" -eq 0 ]; then
                break
            fi
        done

        if [ "$skip" -ne 0 ]; then
            # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
            # At this point we know if we need to either append the $full_rule or group
            # the syscall together with an exsiting rule

            # Append the full_rule if it cannot be grouped to any other rule
            if [ -z ${rule_to_edit+x} ]
            then
                # Build full_rule while avoid adding double spaces when other_filters is empty
                if [ "${#syscall_a[@]}" -gt 0 ]
                then
                    syscall_string=""
                    for syscall in "${syscall_a[@]}"
                    do
                        syscall_string+=" -S $syscall"
                    done
                fi
                other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
                auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
                full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
                echo "$full_rule" >> "$default_file"
                chmod o-rwx ${default_file}
            else
                # Check if the syscalls are declared as a comma separated list or
                # as multiple -S parameters
                if grep -q -- "," <<< "${rule_syscalls_to_edit}"
                then
                    delimiter=","
                else
                    delimiter=" -S "
                fi
                new_grouped_syscalls="${rule_syscalls_to_edit}"
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                       # A syscall was not found in the candidate rule
                       new_grouped_syscalls+="${delimiter}${syscall}"
                       }
                done

                # Group the syscall in the rule
                sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
            fi
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_stime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Perform remediation of Audit rules for stime syscall for x86 platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - stime
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of stime in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_time_rules.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_time_rules.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - stime
          syscall_grouping:
          - adjtimex
          - settimeofday
          - stime

      - name: Check existence of stime in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_time_rules
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ( not ( ansible_architecture == "aarch64" ) and not ( ansible_architecture ==
        "s390x" ) )
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - audit_rules_time_stime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Attempts to Alter the localtime File [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -w /etc/localtime -p wa -k audit_time_rules

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -w /etc/localtime -p wa -k audit_time_rules

The -k option allows for the specification of a key in string form that can be used for better reporting capability through ausearch and aureport and should always be used.

Rationale: | Arbitrary changes to the system time can be used to obfuscate nefarious activities in log files, as well as to confuse network services that are highly dependent upon an accurate system time (such as sshd). All changes to the system time should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_time_watch_localtime

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-001487, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.4.2.b, 10.6.3, 10.6.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_time_rules.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/localtime" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_time_rules.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_time_rules.rules"
        # If the audit_time_rules.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/localtime" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/localtime $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/localtime$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/localtime -p wa -k audit_time_rules" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/localtime already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_time_rules
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_time_rules$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_time_rules.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_time_rules.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/localtime in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/localtime -p wa -k audit_time_rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/localtime already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/localtime\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/localtime in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/localtime -p wa -k audit_time_rules
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.2.b
      - PCI-DSSv4-10.6.3
      - PCI-DSSv4-10.6.3
      - audit_rules_time_watch_localtime
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Make the auditd Configuration Immutable [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to make the auditd configuration immutable:

    -e 2

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file in order to make the auditd configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

Rationale: | Making the audit configuration immutable prevents accidental as well as malicious modification of the audit rules, although it may be problematic if legitimate changes are needed during system operation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_immutable

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.4.3, CCI-000162, CCI-000163, CCI-000164, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.310(a)(2)(iv), 164.312(d), 164.310(d)(2)(iii), 164.312(b), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.2, 10.3.2, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-APP-000119-CTR-000245, SRG-APP-000120-CTR-000250

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Traverse all of:
    #
    # /etc/audit/audit.rules,			(for auditctl case)
    # /etc/audit/rules.d/*.rules			(for augenrules case)
    #
    # files to check if '-e .*' setting is present in that '*.rules' file already.
    # If found, delete such occurrence since auditctl(8) manual page instructs the
    # '-e 2' rule should be placed as the last rule in the configuration
    find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-e[[:space:]]\+.*/d' {} ';'

    # Append '-e 2' requirement at the end of both:
    # * /etc/audit/audit.rules file 		(for auditctl case)
    # * /etc/audit/rules.d/immutable.rules		(for augenrules case)

    for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
    do
    	echo '' >> $AUDIT_FILE
    	echo '# Set the audit.rules configuration immutable per security requirements' >> $AUDIT_FILE
    	echo '# Reboot is required to change audit rules once this setting is applied' >> $AUDIT_FILE
    	echo '-e 2' >> $AUDIT_FILE
    	chmod o-rwx $AUDIT_FILE
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-171-3.4.3
      - NIST-800-53-AC-6(9)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.2
      - PCI-DSSv4-10.3.2
      - audit_rules_immutable
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Collect all files from /etc/audit/rules.d with .rules extension
      find:
        paths: /etc/audit/rules.d/
        patterns: '*.rules'
      register: find_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-171-3.4.3
      - NIST-800-53-AC-6(9)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.2
      - PCI-DSSv4-10.3.2
      - audit_rules_immutable
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Remove the -e option from all Audit config files
      lineinfile:
        path: '{{ item }}'
        regexp: ^\s*(?:-e)\s+.*$
        state: absent
      loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
        }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-171-3.4.3
      - NIST-800-53-AC-6(9)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.2
      - PCI-DSSv4-10.3.2
      - audit_rules_immutable
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add Audit -e option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
      lineinfile:
        path: '{{ item }}'
        create: true
        line: -e 2
        mode: o-rwx
      loop:
      - /etc/audit/audit.rules
      - /etc/audit/rules.d/immutable.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-171-3.4.3
      - NIST-800-53-AC-6(9)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.2
      - PCI-DSSv4-10.3.2
      - audit_rules_immutable
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Mandatory Access Controls [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -w /etc/selinux/ -p wa -k MAC-policy

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -w /etc/selinux/ -p wa -k MAC-policy

Rationale: | The system's mandatory access policy (SELinux) should not be arbitrarily changed by anything other than administrator action. All changes to MAC policy should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_mac_modification

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.8, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.5, 10.3.4

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/MAC-policy.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/selinux/" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/MAC-policy.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/MAC-policy.rules"
        # If the MAC-policy.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/selinux/" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/selinux/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/selinux/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/selinux/ -p wa -k MAC-policy" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key MAC-policy
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)MAC-policy$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/MAC-policy.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/MAC-policy.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/selinux/ in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/selinux/ -p wa -k MAC-policy
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/selinux/ already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/selinux/\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/selinux/ in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/selinux/ -p wa -k MAC-policy
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.8
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_mac_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects Information on Exporting to Media (successful) [ref]

At a minimum, the audit system should collect media exportation events for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=1000 -F auid!=unset -F key=export

Rationale: | The unauthorized exportation of data to external media could result in an information leak where classified information, Privacy Act information, and intellectual property could be lost. An audit trail should be created each time a filesystem is mounted to help identify and guard against information loss.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_media_export

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.2.7, 10.2.1.7, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-APP-000495-CTR-001235, OL07-00-030740, SV-221813r860882_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS="-F auid>=1000 -F auid!=unset"
    	SYSCALL="mount"
    	KEY="perm_mod"
    	SYSCALL_GROUPING=""

    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030740
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_media_export
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Set architecture for audit mount tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030740
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_media_export
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for mount for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - mount
          syscall_grouping: []

      - name: Check existence of mount in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - mount
          syscall_grouping: []

      - name: Check existence of mount in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030740
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_media_export
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Perform remediation of Audit rules for mount for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - mount
          syscall_grouping: []

      - name: Check existence of mount in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/perm_mod.rules
        set_fact: audit_file="/etc/audit/rules.d/perm_mod.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k
            |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - mount
          syscall_grouping: []

      - name: Check existence of mount in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* -F auid>=1000 -F auid!=unset (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( -F auid>=1000 -F auid!=unset (?:-k |-F
            key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F auid>=1000
            -F auid!=unset -F key=perm_mod
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030740
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.7
      - PCI-DSSv4-10.2.1.7
      - audit_rules_media_export
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify the System's Network Environment [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
    -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S sethostname,setdomainname -F key=audit_rules_networkconfig_modification
    -w /etc/issue -p wa -k audit_rules_networkconfig_modification
    -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
    -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
    -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification

Rationale: | The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_networkconfig_modification

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, Req-10.5.5, 10.3.4

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # First perform the remediation of the syscall rule
    # Retrieve hardware architecture of the underlying system
    [ "$(getconf LONG_BIT)" = "32" ] && RULE_ARCHS=("b32") || RULE_ARCHS=("b32" "b64")

    for ARCH in "${RULE_ARCHS[@]}"
    do
    	ACTION_ARCH_FILTERS="-a always,exit -F arch=$ARCH"
    	OTHER_FILTERS=""
    	AUID_FILTERS=""
    	SYSCALL="sethostname setdomainname"
    	KEY="audit_rules_networkconfig_modification"
    	SYSCALL_GROUPING="sethostname setdomainname"
    	# Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'augenrules', then check if the audit rule is defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to the list for inspection
    # If rule isn't defined yet, add '/etc/audit/rules.d/$key.rules' to the list for inspection
    default_file="/etc/audit/rules.d/$KEY.rules"
    # As other_filters may include paths, lets use a different delimiter for it
    # The "F" script expression tells sed to print the filenames where the expressions matched
    readarray -t files_to_inspect < <(sed -s -n -e "/^$ACTION_ARCH_FILTERS/!d" -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" -e "F" /etc/audit/rules.d/*.rules)
    # Case when particular rule isn't defined in /etc/audit/rules.d/*.rules yet
    if [ ${#files_to_inspect[@]} -eq "0" ]
    then
        file_to_inspect="/etc/audit/rules.d/$KEY.rules"
        files_to_inspect=("$file_to_inspect")
        if [ ! -e "$file_to_inspect" ]
        then
            touch "$file_to_inspect"
            chmod 0640 "$file_to_inspect"
        fi
    fi

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    	unset syscall_a
    unset syscall_grouping
    unset syscall_string
    unset syscall
    unset file_to_edit
    unset rule_to_edit
    unset rule_syscalls_to_edit
    unset other_string
    unset auid_string
    unset full_rule

    # Load macro arguments into arrays
    read -a syscall_a <<< $SYSCALL
    read -a syscall_grouping <<< $SYSCALL_GROUPING

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    #  Tool used to load audit rules | Rule already defined  |  Audit rules file to inspect    |
    # -----------------------------------------------------------------------------------------
    #        auditctl                |     Doesn't matter    |  /etc/audit/audit.rules         |
    # -----------------------------------------------------------------------------------------
    #        augenrules              |          Yes          |  /etc/audit/rules.d/*.rules     |
    #        augenrules              |          No           |  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    #
    files_to_inspect=()

    # If audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # file to the list of files to be inspected
    default_file="/etc/audit/audit.rules"
    files_to_inspect+=('/etc/audit/audit.rules' )

    # After converting to jinja, we cannot return; therefore we skip the rest of the macro if needed instead
    skip=1

    for audit_file in "${files_to_inspect[@]}"
    do
        # Filter existing $audit_file rules' definitions to select those that satisfy the rule pattern,
        # i.e, collect rules that match:
        # * the action, list and arch, (2-nd argument)
        # * the other filters, (3-rd argument)
        # * the auid filters, (4-rd argument)
        readarray -t similar_rules < <(sed -e "/^$ACTION_ARCH_FILTERS/!d"  -e "\#$OTHER_FILTERS#!d" -e "/$AUID_FILTERS/!d" "$audit_file")

        candidate_rules=()
        # Filter out rules that have more fields then required. This will remove rules more specific than the required scope
        for s_rule in "${similar_rules[@]}"
        do
            # Strip all the options and fields we know of,
            # than check if there was any field left over
            extra_fields=$(sed -E -e "s/^$ACTION_ARCH_FILTERS//"  -e "s#$OTHER_FILTERS##" -e "s/$AUID_FILTERS//" -e "s/((:?-S [[:alnum:],]+)+)//g" -e "s/-F key=\w+|-k \w+//"<<< "$s_rule")
            grep -q -- "-F" <<< "$extra_fields" || candidate_rules+=("$s_rule")
        done

        if [[ ${#syscall_a[@]} -ge 1 ]]
        then
            # Check if the syscall we want is present in any of the similar existing rules
            for rule in "${candidate_rules[@]}"
            do
                rule_syscalls=$(echo "$rule" | grep -o -P '(-S [\w,]+)+' | xargs)
                all_syscalls_found=0
                for syscall in "${syscall_a[@]}"
                do
                    grep -q -- "\b${syscall}\b" <<< "$rule_syscalls" || {
                       # A syscall was not found in the candidate rule
                       all_syscalls_found=1
                       }
                done
                if [[ $all_syscalls_found -eq 0 ]]
                then
                    # We found a rule with all the syscall(s) we want; skip rest of macro
                    skip=0
                    break
                fi

                # Check if this rule can be grouped with our target syscall and keep track of it
                for syscall_g in "${syscall_grouping[@]}"
                do
                    if grep -q -- "\b${syscall_g}\b" <<< "$rule_syscalls"
                    then
                        file_to_edit=${audit_file}
                        rule_to_edit=${rule}
                        rule_syscalls_to_edit=${rule_syscalls}
                    fi
                done
            done
        else
            # If there is any candidate rule, it is compliant; skip rest of macro
            if [ "${#candidate_rules[@]}" -gt 0 ]
            then
                skip=0
            fi
        fi

        if [ "$skip" -eq 0 ]; then
            break
        fi
    done

    if [ "$skip" -ne 0 ]; then
        # We checked all rules that matched the expected resemblance pattern (action, arch & auid)
        # At this point we know if we need to either append the $full_rule or group
        # the syscall together with an exsiting rule

        # Append the full_rule if it cannot be grouped to any other rule
        if [ -z ${rule_to_edit+x} ]
        then
            # Build full_rule while avoid adding double spaces when other_filters is empty
            if [ "${#syscall_a[@]}" -gt 0 ]
            then
                syscall_string=""
                for syscall in "${syscall_a[@]}"
                do
                    syscall_string+=" -S $syscall"
                done
            fi
            other_string=$([[ $OTHER_FILTERS ]] && echo " $OTHER_FILTERS") || /bin/true
            auid_string=$([[ $AUID_FILTERS ]] && echo " $AUID_FILTERS") || /bin/true
            full_rule="$ACTION_ARCH_FILTERS${syscall_string}${other_string}${auid_string} -F key=$KEY" || /bin/true
            echo "$full_rule" >> "$default_file"
            chmod o-rwx ${default_file}
        else
            # Check if the syscalls are declared as a comma separated list or
            # as multiple -S parameters
            if grep -q -- "," <<< "${rule_syscalls_to_edit}"
            then
                delimiter=","
            else
                delimiter=" -S "
            fi
            new_grouped_syscalls="${rule_syscalls_to_edit}"
            for syscall in "${syscall_a[@]}"
            do
                grep -q -- "\b${syscall}\b" <<< "${rule_syscalls_to_edit}" || {
                   # A syscall was not found in the candidate rule
                   new_grouped_syscalls+="${delimiter}${syscall}"
                   }
            done

            # Group the syscall in the rule
            sed -i -e "\#${rule_to_edit}#s#${rule_syscalls_to_edit}#${new_grouped_syscalls}#" "$file_to_edit"
        fi
    fi
    done

    # Then perform the remediations for the watch rules
    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/issue" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/issue$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/issue -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/issue.net" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/issue.net" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/issue.net $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/issue.net$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/issue.net -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/hosts" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/hosts" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/hosts $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/hosts$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/hosts -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sysconfig/network" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_networkconfig_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        # If the audit_rules_networkconfig_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sysconfig/network" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sysconfig/network $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sysconfig/network$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set architecture for audit tasks
      set_fact:
        audit_arch: b64
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_architecture == "aarch64" or ansible_architecture == "ppc64" or ansible_architecture
        == "ppc64le" or ansible_architecture == "s390x" or ansible_architecture == "x86_64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Remediate audit rules for network configuration for 32bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - sethostname
          - setdomainname
          syscall_grouping:
          - sethostname
          - setdomainname

      - name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - sethostname
          - setdomainname
          syscall_grouping:
          - sethostname
          - setdomainname

      - name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b32(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b32)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b32 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Remediate audit rules for network configuration for 64bit platform
      block:

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - sethostname
          - setdomainname
          syscall_grouping:
          - sethostname
          - setdomainname

      - name: Check existence of sethostname, setdomainname in /etc/audit/rules.d/
        find:
          paths: /etc/audit/rules.d
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: '*.rules'
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Reset syscalls found per file
        set_fact:
          syscalls_per_file: {}
          found_paths_dict: {}

      - name: Declare syscalls found per file
        set_fact: syscalls_per_file="{{ syscalls_per_file | combine( {item.files[0].path
          :[item.item] + syscalls_per_file.get(item.files[0].path, []) } ) }}"
        loop: '{{ find_command.results | selectattr(''matched'') | list }}'

      - name: Declare files where syscalls were found
        set_fact: found_paths="{{ find_command.results | map(attribute='files') | flatten
          | map(attribute='path') | list }}"

      - name: Count occurrences of syscalls in paths
        set_fact: found_paths_dict="{{ found_paths_dict | combine({ item:1+found_paths_dict.get(item,
          0) }) }}"
        loop: '{{ find_command.results | map(attribute=''files'') | flatten | map(attribute=''path'')
          | list }}'

      - name: Get path with most syscalls
        set_fact: audit_file="{{ (found_paths_dict | dict2items() | sort(attribute='value')
          | last).key }}"
        when: found_paths | length >= 1

      - name: No file with syscall found, set path to /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
        set_fact: audit_file="/etc/audit/rules.d/audit_rules_networkconfig_modification.rules"
        when: found_paths | length == 0

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_per_file[audit_file]
            | join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0

      - name: Declare list of syscalls
        set_fact:
          syscalls:
          - sethostname
          - setdomainname
          syscall_grouping:
          - sethostname
          - setdomainname

      - name: Check existence of sethostname, setdomainname in /etc/audit/audit.rules
        find:
          paths: /etc/audit
          contains: -a always,exit -F arch=b64(( -S |,)\w+)*(( -S |,){{ item }})+(( -S
            |,)\w+)* (-k\s+|-F\s+key=)\S+\s*$
          patterns: audit.rules
        register: find_command
        loop: '{{ (syscall_grouping + syscalls) | unique }}'

      - name: Set path to /etc/audit/audit.rules
        set_fact: audit_file="/etc/audit/audit.rules"

      - name: Declare found syscalls
        set_fact: syscalls_found="{{ find_command.results | selectattr('matched') | map(attribute='item')
          | list }}"

      - name: Declare missing syscalls
        set_fact: missing_syscalls="{{ syscalls | difference(syscalls_found) }}"

      - name: Replace the audit rule in {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          regexp: (-a always,exit -F arch=b64)(?=.*(?:(?:-S |,)(?:{{ syscalls_found |
            join("|") }}))\b)((?:( -S |,)\w+)+)( (?:-k |-F key=)\w+)
          line: \1\2\3{{ missing_syscalls | join("\3") }}\4
          backrefs: true
          state: present
        when: syscalls_found | length > 0 and missing_syscalls | length > 0

      - name: Add the audit rule to {{ audit_file }}
        lineinfile:
          path: '{{ audit_file }}'
          line: -a always,exit -F arch=b64 -S {{ syscalls | join(',') }} -F key=audit_rules_networkconfig_modification
          create: true
          mode: o-rwx
          state: present
        when: syscalls_found | length == 0
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - audit_arch == "b64"
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/issue already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
        recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/issue in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/issue already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/issue\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/issue in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/issue -p wa -k audit_rules_networkconfig_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/issue.net already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
        recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/issue.net in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/issue.net already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/issue.net\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/issue.net in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/issue.net -p wa -k audit_rules_networkconfig_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/hosts already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
        recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/hosts in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/hosts already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/hosts\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/hosts in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/hosts -p wa -k audit_rules_networkconfig_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_networkconfig_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_networkconfig_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_networkconfig_modification.rules as the
        recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_networkconfig_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sysconfig/network in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sysconfig/network already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/sysconfig/network\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sysconfig/network in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/sysconfig/network -p wa -k audit_rules_networkconfig_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.5
      - PCI-DSSv4-10.3.4
      - audit_rules_networkconfig_modification
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Record Attempts to Alter Process and Session Initiation Information [ref]

The audit system already collects process information for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d` in order to watch for attempted manual edits of files involved in storing such process information:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file in order to watch for attempted manual edits of files involved in storing such process information:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Rationale: | Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_session_events

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, 0582, 0584, 05885, 0586, 0846, 0957, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AU-2(d), AU-12(c), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.3, 10.2.1.3, SRG-APP-000505-CTR-001285

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/run/utmp" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/session.rules"
        # If the session.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/run/utmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/run/utmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/run/utmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/run/utmp -p wa -k session" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/btmp" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/session.rules"
        # If the session.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/btmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/btmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/btmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/btmp -p wa -k session" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/session.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/var/log/wtmp" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/session.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/session.rules"
        # If the session.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/var/log/wtmp" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/var/log/wtmp $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/var/log/wtmp$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /var/log/wtmp -p wa -k session" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/run/utmp already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key session
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)session$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/session.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/run/utmp in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /var/run/utmp -p wa -k session
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/run/utmp already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/var/run/utmp\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/run/utmp in /etc/audit/audit.rules
      lineinfile:
        line: -w /var/run/utmp -p wa -k session
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/btmp already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key session
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)session$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/session.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/btmp in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /var/log/btmp -p wa -k session
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/btmp already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/var/log/btmp\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/btmp in /etc/audit/audit.rules
      lineinfile:
        line: -w /var/log/btmp -p wa -k session
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key session
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)session$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/session.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/session.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/wtmp in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /var/log/wtmp -p wa -k session
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /var/log/wtmp already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/var/log/wtmp\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /var/log/wtmp in /etc/audit/audit.rules
      lineinfile:
        line: -w /var/log/wtmp -p wa -k session
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.1.7
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.3
      - PCI-DSSv4-10.2.1.3
      - audit_rules_session_events
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Ensure auditd Collects System Administrator Actions [ref]

At a minimum, the audit system should collect administrator actions for all users and root. If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -w /etc/sudoers -p wa -k actions
    -w /etc/sudoers.d/ -p wa -k actions

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to `/etc/audit/audit.rules` file:

    -w /etc/sudoers -p wa -k actions
    -w /etc/sudoers.d/ -p wa -k actions

Rationale: | The actions taken by system administrators should be audited to keep a record of what was executed on the system, as well as, for accountability purposes.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_sysadmin_actions

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000126, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, AC-2(7)(b), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.2, Req-10.2.5.b, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000026-CTR-000070, SRG-APP-000027-CTR-000075, SRG-APP-000028-CTR-000080, SRG-APP-000291-CTR-000675, SRG-APP-000292-CTR-000680, SRG-APP-000293-CTR-000685, SRG-APP-000294-CTR-000690, SRG-APP-000319-CTR-000745, SRG-APP-000320-CTR-000750, SRG-APP-000509-CTR-001305, OL07-00-030700, SV-221810r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/actions.rules"
        # If the actions.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sudoers$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sudoers -p wa -k actions" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/actions.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/sudoers.d/" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/actions.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/actions.rules"
        # If the actions.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/sudoers.d/" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/sudoers.d/ $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/sudoers.d/$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/sudoers.d/ -p wa -k actions" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sudoers already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sudoers in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/sudoers -p wa -k actions
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sudoers already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/sudoers\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key actions
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)actions$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/actions.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sudoers in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/sudoers -p wa -k actions
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sudoers.d/ in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/sudoers.d/ -p wa -k actions
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Check if watch rule for /etc/sudoers.d/ already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/sudoers.d/\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key actions
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)actions$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use /etc/audit/rules.d/actions.rules as the recipient for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/actions.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Add watch rule for /etc/sudoers.d/ in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/sudoers.d/ -p wa -k actions
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030700
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(7)(b)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.2
      - PCI-DSS-Req-10.2.5.b
      - PCI-DSSv4-10.2.1.5
      - audit_rules_sysadmin_actions
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Shutdown System When Auditing Failures Occur [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following line to to the bottom of a file with suffix `.rules` in the directory `/etc/audit/rules.d`:

    -f 2

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following line to the bottom of the `/etc/audit/audit.rules` file:

    -f 2

Rationale:

It is critical for the appropriate personnel to be aware if a system is at risk of failing to process audit logs as required. Without this notification, the security personnel may be unaware of an impending failure of the audit capability, and system operation may be adversely affected.
Audit processing failures include software/hardware errors, failures in the audit capturing mechanisms, and audit storage capacity being reached or exceeded.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_system_shutdown

Identifiers and References

References: 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 3.3.1, 3.3.4, CCI-000139, CCI-000140, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, AU-5(b), SC-24, CM-6(a), PR.PT-1, SRG-OS-000046-GPOS-00022, SRG-OS-000047-GPOS-00023, OL07-00-030010, SV-221765r880594_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_audit_failure_mode='2'

    # Traverse all of:
    #
    # /etc/audit/audit.rules,			(for auditctl case)
    # /etc/audit/rules.d/*.rules			(for augenrules case)
    find /etc/audit /etc/audit/rules.d -maxdepth 1 -type f -name '*.rules' -exec sed -i '/-f[[:space:]]\+.*/d' {} ';'

    for AUDIT_FILE in "/etc/audit/audit.rules" "/etc/audit/rules.d/immutable.rules"
    do
    	echo '' >> $AUDIT_FILE
    	echo '# Set the audit.rules configuration to halt system upon audit failure per security requirements' >> $AUDIT_FILE
    	echo "-f $var_audit_failure_mode" >> $AUDIT_FILE
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-030010
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.4
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-24
      - audit_rules_system_shutdown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy
    - name: XCCDF Value var_audit_failure_mode # promote to variable
      set_fact:
        var_audit_failure_mode: !!str 2
      tags:
        - always

    - name: Collect all files from /etc/audit/rules.d with .rules extension
      find:
        paths: /etc/audit/rules.d/
        patterns: '*.rules'
      register: find_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030010
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.4
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-24
      - audit_rules_system_shutdown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Remove the -f option from all Audit config files
      lineinfile:
        path: '{{ item }}'
        regexp: ^\s*(?:-f)\s+.*$
        state: absent
      loop: '{{ find_rules_d.files | map(attribute=''path'') | list + [''/etc/audit/audit.rules'']
        }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030010
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.4
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-24
      - audit_rules_system_shutdown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add Audit -f option into /etc/audit/rules.d/immutable.rules and /etc/audit/audit.rules
      lineinfile:
        path: '{{ item }}'
        create: true
        line: -f {{ var_audit_failure_mode }}
      loop:
      - /etc/audit/audit.rules
      - /etc/audit/rules.d/immutable.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-030010
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.4
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-24
      - audit_rules_system_shutdown
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify User/Group Information - /etc/group [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, in order to capture events that modify account changes:

    -w /etc/group -p wa -k audit_rules_usergroup_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, in order to capture events that modify account changes:

    -w /etc/group -p wa -k audit_rules_usergroup_modification

Rationale: | In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_group

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, OL07-00-030871, SV-221826r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/group" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
        # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/group" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/group $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/group$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/group -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/group already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
        for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/group in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/group -p wa -k audit_rules_usergroup_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/group already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/group\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/group in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/group -p wa -k audit_rules_usergroup_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030871
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_group
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify User/Group Information - /etc/gshadow [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, in order to capture events that modify account changes:

    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, in order to capture events that modify account changes:

    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification

Rationale: | In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_gshadow

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, OL07-00-030872, SV-221827r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/gshadow" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
        # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/gshadow" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/gshadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/gshadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/gshadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/gshadow already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
        for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/gshadow in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/gshadow already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/gshadow\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/gshadow in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030872
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_gshadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify User/Group Information - /etc/security/opasswd [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, in order to capture events that modify account changes:

    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, in order to capture events that modify account changes:

    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

Rationale: | In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_opasswd

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000496-CTR-001240, SRG-APP-000497-CTR-001245, SRG-APP-000498-CTR-001250, SRG-APP-000503-CTR-001275, OL07-00-030874, SV-221829r744089_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/security/opasswd" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
        # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/security/opasswd" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/security/opasswd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/security/opasswd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
        for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/security/opasswd in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/security/opasswd already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/security/opasswd\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/security/opasswd in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030874
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_opasswd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify User/Group Information - /etc/passwd [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, in order to capture events that modify account changes:

    -w /etc/passwd -p wa -k audit_rules_usergroup_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, in order to capture events that modify account changes:

    -w /etc/passwd -p wa -k audit_rules_usergroup_modification

Rationale: | In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_passwd

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000304-GPOS-00121, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-OS-000274-GPOS-00104, SRG-OS-000275-GPOS-00105, SRG-OS-000276-GPOS-00106, SRG-OS-000277-GPOS-00107, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, OL07-00-030870, SV-221825r853712_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/passwd" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
        # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/passwd" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/passwd $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/passwd$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/passwd -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/passwd already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
        for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/passwd in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/passwd already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/passwd\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/passwd in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/passwd -p wa -k audit_rules_usergroup_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030870
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_passwd
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule Record Events that Modify User/Group Information - /etc/shadow [ref]

If the `auditd` daemon is configured to use the `augenrules` program to read audit rules during daemon startup (the default), add the following lines to a file with suffix `.rules` in the directory `/etc/audit/rules.d`, in order to capture events that modify account changes:

    -w /etc/shadow -p wa -k audit_rules_usergroup_modification

If the `auditd` daemon is configured to use the `auditctl` utility to read audit rules during daemon startup, add the following lines to `/etc/audit/audit.rules` file, in order to capture events that modify account changes:

    -w /etc/shadow -p wa -k audit_rules_usergroup_modification

Rationale: | In addition to auditing new user and group accounts, these watches will alert the system administrator(s) to any modifications. Any unexpected users, groups, or modifications should be investigated for legitimacy.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_usergroup_modification_shadow

Identifiers and References

References: BP28(R73), 1, 11, 12, 13, 14, 15, 16, 18, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS06.03, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.1.7, CCI-000018, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001403, CCI-001404, CCI-001405, CCI-001683, CCI-001684, CCI-001685, CCI-001686, CCI-002130, CCI-002132, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.2.3.10, 4.3.2.6.7, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.8, 4.3.3.6.6, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.2, CIP-004-6 R2.2.3, CIP-007-3 R.1.3, CIP-007-3 R5, CIP-007-3 R5.1.1, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, AC-2(4), AU-2(d), AU-12(c), AC-6(9), CM-6(a), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.2.5, 10.2.1.5, SRG-OS-000004-GPOS-00004, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000304-GPOS-00121, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000466-GPOS-00210, SRG-OS-000476-GPOS-00221, SRG-APP-000495-CTR-001235, SRG-APP-000499-CTR-001255, SRG-APP-000503-CTR-001275, OL07-00-030873, SV-221828r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    # Perform the remediation for both possible tools: 'auditctl' and 'augenrules'

    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit tool is 'auditctl', then add '/etc/audit/audit.rules'
    # into the list of files to be inspected
    files_to_inspect+=('/etc/audit/audit.rules')

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done
    # Create a list of audit *.rules files that should be inspected for presence and correctness
    # of a particular audit rule. The scheme is as follows:
    #
    # -----------------------------------------------------------------------------------------
    # Tool used to load audit rules	| Rule already defined	|  Audit rules file to inspect	  |
    # -----------------------------------------------------------------------------------------
    #	auditctl		|     Doesn't matter	|  /etc/audit/audit.rules	  |
    # -----------------------------------------------------------------------------------------
    # 	augenrules		|          Yes		|  /etc/audit/rules.d/*.rules	  |
    # 	augenrules		|          No		|  /etc/audit/rules.d/$key.rules  |
    # -----------------------------------------------------------------------------------------
    files_to_inspect=()

    # If the audit is 'augenrules', then check if rule is already defined
    # If rule is defined, add '/etc/audit/rules.d/*.rules' to list of files for inspection.
    # If rule isn't defined, add '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' to list of files for inspection.
    readarray -t matches < <(grep -HP "[\s]*-w[\s]+/etc/shadow" /etc/audit/rules.d/*.rules)

    # For each of the matched entries
    for match in "${matches[@]}"
    do
        # Extract filepath from the match
        rulesd_audit_file=$(echo $match | cut -f1 -d ':')
        # Append that path into list of files for inspection
        files_to_inspect+=("$rulesd_audit_file")
    done
    # Case when particular audit rule isn't defined yet
    if [ "${#files_to_inspect[@]}" -eq "0" ]
    then
        # Append '/etc/audit/rules.d/audit_rules_usergroup_modification.rules' into list of files for inspection
        key_rule_file="/etc/audit/rules.d/audit_rules_usergroup_modification.rules"
        # If the audit_rules_usergroup_modification.rules file doesn't exist yet, create it with correct permissions
        if [ ! -e "$key_rule_file" ]
        then
            touch "$key_rule_file"
            chmod 0640 "$key_rule_file"
        fi
        files_to_inspect+=("$key_rule_file")
    fi

    # Finally perform the inspection and possible subsequent audit rule
    # correction for each of the files previously identified for inspection
    for audit_rules_file in "${files_to_inspect[@]}"
    do
        # Check if audit watch file system object rule for given path already present
        if grep -q -P -- "^[\s]*-w[\s]+/etc/shadow" "$audit_rules_file"
        then
            # Rule is found => verify yet if existing rule definition contains
            # all of the required access type bits

            # Define BRE whitespace class shortcut
            sp="[[:space:]]"
            # Extract current permission access types (e.g. -p [r|w|x|a] values) from audit rule
            current_access_bits=$(sed -ne "s#$sp*-w$sp\+/etc/shadow $sp\+-p$sp\+\([rxwa]\{1,4\}\).*#\1#p" "$audit_rules_file")
            # Split required access bits string into characters array
            # (to check bit's presence for one bit at a time)
            for access_bit in $(echo "wa" | grep -o .)
            do
                # For each from the required access bits (e.g. 'w', 'a') check
                # if they are already present in current access bits for rule.
                # If not, append that bit at the end
                if ! grep -q "$access_bit" <<< "$current_access_bits"
                then
                    # Concatenate the existing mask with the missing bit
                    current_access_bits="$current_access_bits$access_bit"
                fi
            done
            # Propagate the updated rule's access bits (original + the required
            # ones) back into the /etc/audit/audit.rules file for that rule
            sed -i "s#\($sp*-w$sp\+/etc/shadow$sp\+-p$sp\+\)\([rxwa]\{1,4\}\)\(.*\)#\1$current_access_bits\3#" "$audit_rules_file"
        else
            # Rule isn't present yet. Append it at the end of $audit_rules_file file
            # with proper key

            echo "-w /etc/shadow -p wa -k audit_rules_usergroup_modification" >> "$audit_rules_file"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/shadow already exists in /etc/audit/rules.d/
      find:
        paths: /etc/audit/rules.d
        contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
        patterns: '*.rules'
      register: find_existing_watch_rules_d
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Search /etc/audit/rules.d for other rules with specified key audit_rules_usergroup_modification
      find:
        paths: /etc/audit/rules.d
        contains: ^.*(?:-F key=|-k\s+)audit_rules_usergroup_modification$
        patterns: '*.rules'
      register: find_watch_key
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use /etc/audit/rules.d/audit_rules_usergroup_modification.rules as the recipient
        for the rule
      set_fact:
        all_files:
        - /etc/audit/rules.d/audit_rules_usergroup_modification.rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched == 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Use matched file as the recipient for the rule
      set_fact:
        all_files:
        - '{{ find_watch_key.files | map(attribute=''path'') | list | first }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_watch_key.matched is defined and find_watch_key.matched > 0 and find_existing_watch_rules_d.matched
        is defined and find_existing_watch_rules_d.matched == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/shadow in /etc/audit/rules.d/
      lineinfile:
        path: '{{ all_files[0] }}'
        line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_rules_d.matched is defined and find_existing_watch_rules_d.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check if watch rule for /etc/shadow already exists in /etc/audit/audit.rules
      find:
        paths: /etc/audit/
        contains: ^\s*-w\s+/etc/shadow\s+-p\s+wa(\s|$)+
        patterns: audit.rules
      register: find_existing_watch_audit_rules
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for /etc/shadow in /etc/audit/audit.rules
      lineinfile:
        line: -w /etc/shadow -p wa -k audit_rules_usergroup_modification
        state: present
        dest: /etc/audit/audit.rules
        create: true
        mode: '0640'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - find_existing_watch_audit_rules.matched is defined and find_existing_watch_audit_rules.matched
        == 0
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030873
      - NIST-800-171-3.1.7
      - NIST-800-53-AC-2(4)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.2.5
      - PCI-DSSv4-10.2.1.5
      - audit_rules_usergroup_modification_shadow
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy

#### Rule System Audit Logs Must Be Owned By Root [ref]

All audit logs must be owned by root user and group. By default, the path for audit log is

    /var/log/audit/

. To properly set the owner of `/var/log/audit`, run the command:

    $ sudo chown root /var/log/audit

To properly set the owner of `/var/log/audit/*`, run the command:

    $ sudo chown root /var/log/audit/*

Rationale: | Unauthorized disclosure of audit records can reveal system and configuration data to attackers, thus compromising its confidentiality.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_ownership_var_log_audit

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.1, CCI-000162, CCI-000163, CCI-000164, CCI-001314, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), AU-9(4), DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5.1, 10.3.2, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-APP-000118-CTR-000240, OL07-00-910055, SV-221899r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    if LC_ALL=C grep -m 1 -q ^log_group /etc/audit/auditd.conf; then
      GROUP=$(awk -F "=" '/log_group/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
      if ! [ "${GROUP}" == 'root' ] ; then
        chown root:${GROUP} /var/log/audit
        chown root:${GROUP} /var/log/audit/audit.log*
      else
        chown root:root /var/log/audit
        chown root:root /var/log/audit/audit.log*
      fi
    else
      chown root:root /var/log/audit
      chown root:root /var/log/audit/audit.log*
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

#### Rule System Audit Logs Must Have Mode 0640 or Less Permissive [ref]

Determine where the audit logs are stored with the following command:

    $ sudo grep -iw log_file /etc/audit/auditd.conf
    log_file = /var/log/audit/audit.log

Configure the audit log to be protected from unauthorized read access by setting the correct permissive mode with the following command:

    $ sudo chmod 0600 audit_log_file

By default, audit_log_file is "/var/log/audit/audit.log".

Rationale: | If users can write to audit logs, audit trails can be modified or destroyed.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_var_log_audit

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO01.06, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, DSS06.02, MEA02.01, 3.3.1, CCI-000162, CCI-000163, CCI-000164, CCI-001314, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.7.3, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 5.2, SR 6.1, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.16.1.4, A.16.1.5, A.16.1.7, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), AU-9(4), DE.AE-3, DE.AE-5, PR.AC-4, PR.DS-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.5, 10.3.1, SRG-OS-000057-GPOS-00027, SRG-OS-000058-GPOS-00028, SRG-OS-000059-GPOS-00029, SRG-OS-000206-GPOS-00084, SRG-APP-000118-CTR-000240, OL07-00-910055, SV-221899r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    if LC_ALL=C grep -iw ^log_file /etc/audit/auditd.conf; then
        FILE=$(awk -F "=" '/^log_file/ {print $2}' /etc/audit/auditd.conf | tr -d ' ')
    else
        FILE="/var/log/audit/audit.log"
    fi

    chmod 0600 $FILE

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Get audit log files
      command: grep -iw ^log_file /etc/audit/auditd.conf
      failed_when: false
      register: log_file_exists
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Parse log file line
      command: awk -F '=' '/^log_file/ {print $2}' /etc/audit/auditd.conf
      register: log_file_line
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (log_file_exists.stdout | length > 0)
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set default log_file if not set
      set_fact:
        log_file: /var/log/audit/audit.log
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (log_file_exists is undefined) or (log_file_exists.stdout | length == 0)
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Set log_file from log_file_line if not set already
      set_fact:
        log_file: '{{ log_file_line.stdout | trim }}'
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (log_file_line.stdout is defined) and (log_file_line.stdout | length > 0)
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Apply mode to log file
      file:
        path: '{{ log_file }}'
        mode: 384
      failed_when: false
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-910055
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-6(1)
      - NIST-800-53-AU-9(4)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5
      - PCI-DSSv4-10.3.1
      - file_permissions_var_log_audit
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group Configure auditd Data Retention Group contains 8 rules

[ref] The audit system writes data to `/var/log/audit/audit.log`. By default, `auditd` rotates 5 logs by size (6MB), retaining a maximum of 30MB of data in total, and refuses to write entries when the disk is too full. This minimizes the risk of audit data filling its partition and impacting other services. This also minimizes the risk of the audit daemon temporarily disabling the system if it cannot write audit log (which it can be configured to do). For a busy system or a system which is thoroughly auditing system activity, the default settings for data retention may be insufficient. The log file size needed will depend heavily on what types of events are being audited. First configure auditing to log all the events of interest. Then monitor the log size manually for awhile to determine what file size will allow you to keep the required data for the correct time period.
Using a dedicated partition for `/var/log/audit` prevents the `auditd` logs from disrupting system functionality if they fill, and, more importantly, prevents other activity in `/var` from filling the partition and stopping the audit trail. (The audit logs are size-limited and therefore unlikely to grow without bound unless configured to do so.) Some machines may have requirements that no actions occur which cannot be audited. If this is the case, then `auditd` can be configured to halt the machine if it runs out of space. Note: Since older logs are rotated, configuring `auditd` this way does not prevent older logs from being rotated away before they can be viewed. If your system is configured to halt when logging cannot be performed, make sure this can never happen under normal circumstances! Ensure that `/var/log/audit` is on its own partition, and that this partition is larger than the maximum amount of data `auditd` will retain normally.

#### Rule Configure auditd to use audispd's syslog plugin [ref]

To configure the `auditd` service to use the `syslog` plug-in of the `audispd` audit event multiplexor, set the `active` line in `/etc/audisp/plugins.d/syslog.conf` to `yes`. Restart the `auditd` service:

    $ sudo service auditd restart

Rationale: | The auditd service does not include the ability to send audit records to a centralized server for management directly. It does, however, include a plug-in for audit event multiplexor (audispd) to pass audit records to the local syslog server.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_audispd_syslog_plugin_activated

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000136, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, AU-4(1), CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, FAU_GEN.1.1.c, Req-10.5.3, 10.3.3, SRG-OS-000479-GPOS-00224, SRG-OS-000342-GPOS-00133

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_syslog_active="yes"

    AUDISP_SYSLOGCONFIG=/etc/audisp/plugins.d/syslog.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^active")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_syslog_active"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^active\\>" "$AUDISP_SYSLOGCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^active\\>.*/$escaped_formatted_output/gi" "$AUDISP_SYSLOGCONFIG"
    else
        if [[ -s "$AUDISP_SYSLOGCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDISP_SYSLOGCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDISP_SYSLOGCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDISP_SYSLOGCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-4(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.3
      - PCI-DSSv4-10.3.3
      - auditd_audispd_syslog_plugin_activated
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Enable syslog plugin
      lineinfile:
        dest: /etc/audisp/plugins.d/syslog.conf
        regexp: ^active
        line: active = yes
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-4(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.5.3
      - PCI-DSSv4-10.3.3
      - auditd_audispd_syslog_plugin_activated
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Configure auditd mail_acct Action on Low Disk Space [ref]

The `auditd` service can be configured to send email to a designated account in certain situations. Add or correct the following line in `/etc/audit/auditd.conf` to ensure that administrators are notified via email for those situations:

    action_mail_acct = root

Rationale: | Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_action_mail_acct

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000139, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, CIP-003-8 R1.3, CIP-003-8 R3, CIP-003-8 R3.1, CIP-003-8 R3.2, CIP-003-8 R3.3, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, IA-5(1), AU-5(a), AU-5(2), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7.a, SRG-OS-000046-GPOS-00022, SRG-OS-000343-GPOS-00134, OL07-00-030350, SV-221776r877389_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_action_mail_acct='root'

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^action_mail_acct")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_action_mail_acct"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^action_mail_acct\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^action_mail_acct\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030350
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)
      - PCI-DSS-Req-10.7.a
      - auditd_data_retention_action_mail_acct
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_action_mail_acct # promote to variable
      set_fact:
        var_auditd_action_mail_acct: !!str root
      tags:
        - always

    - name: Configure auditd mail_acct Action on Low Disk Space
      lineinfile:
        dest: /etc/audit/auditd.conf
        line: action_mail_acct = {{ var_auditd_action_mail_acct }}
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030350
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)
      - PCI-DSS-Req-10.7.a
      - auditd_data_retention_action_mail_acct
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd admin_space_left Action on Low Disk Space [ref]

The `auditd` service can be configured to take an action when disk space is running low but prior to running out of space completely. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting ACTION appropriately:

    admin_space_left_action = ACTION

Set this value to `single` to cause the system to switch to single user mode for corrective action. Acceptable values also include `suspend` and `halt`. For certain systems, the need for availability outweighs the need to log all actions, and a different setting should be determined. Details regarding all possible values for ACTION are described in the `auditd.conf` man page.

Rationale: | Administrators should be made aware of an inability to record audit records. If a separate partition or logical volume of adequate size is used, running low on space for audit records should never occur.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_admin_space_left_action

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-000140, CCI-001343, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 10.5.1, SRG-OS-000343-GPOS-00134

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_admin_space_left_action='single'

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^admin_space_left_action")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_admin_space_left_action"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^admin_space_left_action\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^admin_space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - PCI-DSSv4-10.5.1
      - auditd_data_retention_admin_space_left_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_admin_space_left_action # promote to variable
      set_fact:
        var_auditd_admin_space_left_action: !!str single
      tags:
        - always

    - name: Configure auditd admin_space_left Action on Low Disk Space
      lineinfile:
        dest: /etc/audit/auditd.conf
        line: admin_space_left_action = {{ var_auditd_admin_space_left_action }}
        regexp: ^\s*admin_space_left_action\s*=\s*.*$
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - PCI-DSSv4-10.5.1
      - auditd_data_retention_admin_space_left_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd flush priority [ref]

The `auditd` service can be configured to synchronously write audit event data to disk. Add or correct the following line in `/etc/audit/auditd.conf` to ensure that audit event data is fully synchronized with the log files on the disk:

    flush = data

Rationale: | Audit data should be synchronously written to disk to ensure log integrity. These parameters assure that all audit event data is fully synchronized with the log files on the disk.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_flush

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 2, 3, 5, 6, 7, 8, 9, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001576, 164.308(a)(1)(ii)(D), 164.308(a)(3)(ii)(A), 164.308(a)(5)(ii)(C), 164.312(a)(2)(i), 164.312(b), 164.312(d), 164.312(e), 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 6.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.14.2.7, A.15.2.1, A.15.2.2, CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AU-11, CM-6(a), DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.PT-1, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_flush='data'

    AUDITCONFIG=/etc/audit/auditd.conf

    # if flush is present, flush param edited to var_auditd_flush
    # else flush param is defined by var_auditd_flush
    #
    # the freq param is only used for values 'incremental' and 'incremental_async' and will be
    # commented out if flush != incremental or flush != incremental_async
    #
    # if flush == incremental or flush == incremental_async && freq param is not defined, it
    # will be defined as the package-default value of 20

    grep -q ^flush $AUDITCONFIG && \
      sed -i 's/^flush.*/flush = '"$var_auditd_flush"'/g' $AUDITCONFIG
    if ! [ $? -eq 0 ]; then
      echo "flush = $var_auditd_flush" >> $AUDITCONFIG
    fi

    if ! [ "$var_auditd_flush" == "incremental" ] && ! [ "$var_auditd_flush" == "incremental_async" ]; then
      sed -i 's/^freq/##freq/g' $AUDITCONFIG
    elif [ "$var_auditd_flush" == "incremental" ] || [ "$var_auditd_flush" == "incremental_async" ]; then
      grep -q freq $AUDITCONFIG && \
        sed -i 's/^#\+freq/freq/g' $AUDITCONFIG
      if ! [ $? -eq 0 ]; then
        echo "freq = 20" >> $AUDITCONFIG
      fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - auditd_data_retention_flush
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_flush # promote to variable
      set_fact:
        var_auditd_flush: !!str data
      tags:
        - always

    - name: Configure auditd Flush Priority
      lineinfile:
        dest: /etc/audit/auditd.conf
        regexp: ^\s*flush\s*=\s*.*$
        line: flush = {{ var_auditd_flush }}
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - auditd_data_retention_flush
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd Max Log File Size [ref]

Determine the amount of audit data (in megabytes) which should be retained in each log file. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting the correct value of 6 for STOREMB:

    max_log_file = STOREMB

Set the value to `6` (MB) or higher for general-purpose systems. Larger values, of course, support retention of even more audit data.

Rationale: | The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AU-11, CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_max_log_file='6'

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^max_log_file\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^max_log_file\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_max_log_file
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_max_log_file # promote to variable
      set_fact:
        var_auditd_max_log_file: !!str 6
      tags:
        - always

    - name: Configure auditd Max Log File Size
      lineinfile:
        dest: /etc/audit/auditd.conf
        regexp: ^\s*max_log_file\s*=\s*.*$
        line: max_log_file = {{ var_auditd_max_log_file }}
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_max_log_file
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd max_log_file_action Upon Reaching Maximum Log Size [ref]

The default action to take when the logs reach their maximum size is to rotate the log files, discarding the oldest one. To configure the action taken by `auditd`, add or correct the line in `/etc/audit/auditd.conf`:

    max_log_file_action = ACTION

Possible values for ACTION are described in the `auditd.conf` man page. These include:

- `ignore`
- `syslog`
- `suspend`
- `rotate`
- `keep_logs`

Set the `ACTION` to `rotate` to ensure log rotation occurs. This is the default. The setting is case-insensitive.

Rationale: | Automatically rotating logs (by setting this to `rotate`) minimizes the chances of the system unexpectedly running out of disk space by being overwhelmed with log data. However, for systems that must never discard log data, or which use external processes to transfer it and reclaim space, `keep_logs` can be employed.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_max_log_file_action

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, CCI-000140, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, SRG-OS-000047-GPOS-00023

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_max_log_file_action='rotate'

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^max_log_file_action")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_max_log_file_action"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^max_log_file_action\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^max_log_file_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_max_log_file_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_max_log_file_action # promote to variable
      set_fact:
        var_auditd_max_log_file_action: !!str rotate
      tags:
        - always

    - name: Configure auditd max_log_file_action Upon Reaching Maximum Log Size
      lineinfile:
        dest: /etc/audit/auditd.conf
        line: max_log_file_action = {{ var_auditd_max_log_file_action }}
        regexp: ^\s*max_log_file_action\s*=\s*.*$
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_max_log_file_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd Number of Logs Retained [ref]

Determine how many log files `auditd` should retain when it rotates logs. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting NUMLOGS with the correct value of 5:

    num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

Rationale: | The total storage for audit log files must be large enough to retain log information over the period required. This is a function of the maximum log file size and the number of logs retained.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_num_logs

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, BAI03.05, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, CIP-004-6 R2.2.3, CIP-004-6 R3.3, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AU-11, CM-6(a), DE.AE-3, DE.AE-5, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_num_logs='5'

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^num_logs")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_num_logs"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^num_logs\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^num_logs\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_num_logs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_num_logs # promote to variable
      set_fact:
        var_auditd_num_logs: !!str 5
      tags:
        - always

    - name: Configure auditd Number of Logs Retained
      lineinfile:
        dest: /etc/audit/auditd.conf
        line: num_logs = {{ var_auditd_num_logs }}
        regexp: ^\s*num_logs\s*=\s*.*$
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-11
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - auditd_data_retention_num_logs
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Configure auditd space_left Action on Low Disk Space [ref]

The `auditd` service can be configured to take an action when disk space starts to run low. Edit the file `/etc/audit/auditd.conf`. Modify the following line, substituting ACTION appropriately:

    space_left_action = ACTION

Possible values for ACTION are described in the `auditd.conf` man page. These include:

- `syslog`
- `email`
- `exec`
- `suspend`
- `single`
- `halt`

Set this to `email` (instead of the default, which is `suspend`) as it is more likely to get prompt attention. Acceptable values also include `suspend`, `single`, and `halt`.

Rationale: | Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_auditd_data_retention_space_left_action

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO11.04, APO12.06, APO13.01, BAI03.05, BAI04.04, BAI08.02, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.04, DSS05.07, MEA02.01, 3.3.1, CCI-001855, 164.312(a)(2)(ii), 4.2.3.10, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, SR 7.1, SR 7.2, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.16.1.4, A.16.1.5, A.16.1.7, A.17.2.1, AU-5(b), AU-5(2), AU-5(1), AU-5(4), CM-6(a), DE.AE-3, DE.AE-5, PR.DS-4, PR.PT-1, RS.AN-1, RS.AN-4, Req-10.7, 10.5.1, SRG-OS-000343-GPOS-00134, OL07-00-030340, SV-221775r877389_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && rpm --quiet -q audit; then

    var_auditd_space_left_action='email'

    #
    # If space_left_action present in /etc/audit/auditd.conf, change value
    # to var_auditd_space_left_action, else
    # add "space_left_action = $var_auditd_space_left_action" to /etc/audit/auditd.conf
    #

    AUDITCONFIG=/etc/audit/auditd.conf

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^space_left_action")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$var_auditd_space_left_action"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^space_left_action\\>" "$AUDITCONFIG"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^space_left_action\\>.*/$escaped_formatted_output/gi" "$AUDITCONFIG"
    else
        if [[ -s "$AUDITCONFIG" ]] && [[ -n "$(tail -c 1 -- "$AUDITCONFIG" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "$AUDITCONFIG"
        fi
        printf '%s\n' "$formatted_output" >> "$AUDITCONFIG"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030340
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - PCI-DSSv4-10.5.1
      - auditd_data_retention_space_left_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
    - name: XCCDF Value var_auditd_space_left_action # promote to variable
      set_fact:
        var_auditd_space_left_action: !!str email
      tags:
        - always

    - name: Configure auditd space_left Action on Low Disk Space
      lineinfile:
        dest: /etc/audit/auditd.conf
        line: space_left_action = {{ var_auditd_space_left_action }}
        regexp: ^\s*space_left_action\s*=\s*.*$
        state: present
        create: true
      when:
      - '"audit" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030340
      - NIST-800-171-3.3.1
      - NIST-800-53-AU-5(1)
      - NIST-800-53-AU-5(2)
      - NIST-800-53-AU-5(4)
      - NIST-800-53-AU-5(b)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.7
      - PCI-DSSv4-10.5.1
      - auditd_data_retention_space_left_action
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

Group System Accounting with auditd Group contains 1 rule
[ref] The `auditd` program can perform comprehensive monitoring of system activity. This section makes use of recommended configuration settings for specific policies or use cases. The rules in this section make use of rules defined in `/usr/share/doc/audit-VERSION/rules`.

#### Rule Configure audit according to OSPP requirements [ref]

Configure audit to meet requirements for Operating System Protection Profile (OSPP) v4.2.1. Audit defines groups of rules in `/usr/share/doc/audit/rules` to satisfy specific policies. To fulfill requirements for compliance with OSPP v4.2.1, the following files are necessary:

- /usr/share/doc/audit-VERSION/rules/10-base-config.rules
- /usr/share/doc/audit-VERSION/rules/11-loginuid.rules
- /usr/share/doc/audit-VERSION/rules/30-ospp-v42.rules
- /usr/share/doc/audit-VERSION/rules/43-module-load.rules

Copy the files from `/usr/share/doc/audit/rules` to `/etc/audit/rules.d`:

    cp /usr/share/doc/audit*/rules/{10-base-config,11-loginuid,30-ospp-v42,43-module-load}.rules /etc/audit/rules.d/

Warning: It might happen that Audit buffer configured by this rule is not large enough for certain use cases. If that is the case, the buffer size can be overridden by placing

    -b larger_buffer_size

into a file within `/etc/audit/rules.d` directory, replacing `larger_file_size` with the desired value. The file name should start with a number higher than 10 and lower than 99.

Rationale: | The audit rules defined in `/usr/share/doc/audit/rules` are the recommended way to meet compliance with OSPP v4.2.1.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_audit_rules_for_ospp

Identifiers and References

References: NONE, FAU_GEN.1.1.c, SRG-OS-000004-GPOS-00004, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000476-GPOS-00221, SRG-OS-000327-GPOS-00127, SRG-OS-000064-GPOS-00033, SRG-OS-000365-GPOS-00152, SRG-OS-000458-GPOS-00203, SRG-OS-000461-GPOS-00205, SRG-OS-000462-GPOS-00206, SRG-OS-000463-GPOS-00207, SRG-OS-000465-GPOS-00209, SRG-OS-000466-GPOS-00210, SRG-OS-000468-GPOS-00212, SRG-OS-000470-GPOS-00214, SRG-OS-000471-GPOS-00215, SRG-OS-000471-GPOS-00216, SRG-OS-000472-GPOS-00217, SRG-OS-000474-GPOS-00219, SRG-OS-000475-GPOS-00220, SRG-OS-000477-GPOS-00222

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    cp /usr/share/doc/audit*/rules/10-base-config.rules /etc/audit/rules.d
    cp /usr/share/doc/audit*/rules/11-loginuid.rules /etc/audit/rules.d
    cp /usr/share/doc/audit*/rules/30-ospp-v42.rules /etc/audit/rules.d
    cp /usr/share/doc/audit*/rules/43-module-load.rules /etc/audit/rules.d

    augenrules --load

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

#### Rule Enable auditd Service [ref]

The `auditd` service is an essential userspace component of the Linux Auditing System, as it is responsible for writing audit records to disk. The `auditd` service can be enabled with the following command:

    $ sudo systemctl enable auditd.service

Rationale:

Without establishing what type of events occurred, it would be difficult to establish, correlate, and investigate the events leading up to an outage or attack. Ensuring the `auditd` service is active ensures audit records generated by the kernel are appropriately recorded.
Additionally, a properly configured audit subsystem ensures that actions of individual system users can be uniquely traced to those users so they can be held accountable for their actions.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_auditd_enabled

Identifiers and References

References: BP28(R33), BP28(R73), 1, 11, 12, 13, 14, 15, 16, 19, 2, 3, 4, 5, 6, 7, 8, 9, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.03, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS03.05, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, 3.3.2, 3.3.6, CCI-000126, CCI-000130, CCI-000131, CCI-000132, CCI-000133, CCI-000134, CCI-000135, CCI-000154, CCI-000158, CCI-000172, CCI-000366, CCI-001464, CCI-001487, CCI-001814, CCI-001875, CCI-001876, CCI-001877, CCI-002884, CCI-001878, CCI-001879, CCI-001880, CCI-001881, CCI-001882, CCI-001889, CCI-001914, CCI-000169, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 6.2, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.7, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, CIP-004-6 R3.3, CIP-007-3 R6.5, AC-2(g), AU-3, AU-10, AU-2(d), AU-12(c), AU-14(1), AC-6(9), CM-6(a), SI-4(23), DE.AE-3, DE.AE-5, DE.CM-1, DE.CM-3, DE.CM-7, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.1, 10.2.1, SRG-OS-000062-GPOS-00031, SRG-OS-000037-GPOS-00015, SRG-OS-000038-GPOS-00016, SRG-OS-000039-GPOS-00017, SRG-OS-000040-GPOS-00018, SRG-OS-000041-GPOS-00019, SRG-OS-000042-GPOS-00021, SRG-OS-000051-GPOS-00024, SRG-OS-000054-GPOS-00025, SRG-OS-000122-GPOS-00063, SRG-OS-000254-GPOS-00095, SRG-OS-000255-GPOS-00096, SRG-OS-000337-GPOS-00129, SRG-OS-000348-GPOS-00136, SRG-OS-000349-GPOS-00137, SRG-OS-000350-GPOS-00138, SRG-OS-000351-GPOS-00139, SRG-OS-000352-GPOS-00140, SRG-OS-000353-GPOS-00141, SRG-OS-000354-GPOS-00142, SRG-OS-000358-GPOS-00145, SRG-OS-000365-GPOS-00152, SRG-OS-000392-GPOS-00172, SRG-OS-000475-GPOS-00220, SRG-APP-000095-CTR-000170, SRG-APP-000409-CTR-000990, SRG-APP-000508-CTR-001300, SRG-APP-000510-CTR-001310, OL07-00-030000, SV-221764r860865_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q audit; }; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" unmask 'auditd.service'
    "$SYSTEMCTL_EXEC" start 'auditd.service'
    "$SYSTEMCTL_EXEC" enable 'auditd.service'

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030000
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.2
      - NIST-800-171-3.3.6
      - NIST-800-53-AC-2(g)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-14(1)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-AU-3
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-4(23)
      - PCI-DSS-Req-10.1
      - PCI-DSSv4-10.2.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_auditd_enabled

    - name: Enable service auditd
      block:

      - name: Gather the package facts
        package_facts:
          manager: auto

      - name: Enable service auditd
        systemd:
          name: auditd
          enabled: 'yes'
          state: started
          masked: 'no'
        when:
        - '"audit" in ansible_facts.packages'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"audit" in ansible_facts.packages'
      tags:
      - CJIS-5.4.1.1
      - DISA-STIG-OL07-00-030000
      - NIST-800-171-3.3.1
      - NIST-800-171-3.3.2
      - NIST-800-171-3.3.6
      - NIST-800-53-AC-2(g)
      - NIST-800-53-AC-6(9)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-12(c)
      - NIST-800-53-AU-14(1)
      - NIST-800-53-AU-2(d)
      - NIST-800-53-AU-3
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SI-4(23)
      - PCI-DSS-Req-10.1
      - PCI-DSSv4-10.2.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_auditd_enabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    enabled = ["auditd"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include enable_auditd

    class enable_auditd {
      service {'auditd':
        enable => true,
        ensure => 'running',
      }
    }

Remediation Kubernetes snippet ⇲

    ---
    apiVersion: machineconfiguration.openshift.io/v1
    kind: MachineConfig
    spec:
      config:
        ignition:
          version: 3.1.0
        systemd:
          units:
          - name: auditd.service
            enabled: true

#### Rule Enable Auditing for Processes Which Start Prior to the Audit Daemon [ref]

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the default GRUB 2 command line for the Linux operating system. To ensure that `audit=1` is added as a kernel command line argument to newly installed kernels, add `audit=1` to the default Grub2 command line for Linux operating systems. Modify the line within `/etc/default/grub` as shown below:

    GRUB_CMDLINE_LINUX="... audit=1 ..."

Run the following command to update command line for already installed kernels:

    # grubby --update-kernel=ALL --args="audit=1"

Rationale: | Each process on the system carries an "auditable" flag which indicates whether its activities can be audited. Although `auditd` takes care of enabling this for all processes which launch after it does, adding the kernel argument ensures it is set for every process during boot.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_audit_argument

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 19, 3, 4, 5, 6, 7, 8, 5.4.1.1, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, APO12.06, APO13.01, BAI03.05, BAI08.02, DSS01.04, DSS02.02, DSS02.04, DSS02.07, DSS03.01, DSS05.02, DSS05.03, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, 3.3.1, CCI-001464, CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-002884, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(C), 164.310(a)(2)(iv), 164.310(d)(2)(iii), 164.312(b), 4.2.3.10, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.3.6.6, 4.3.4.4.7, 4.3.4.5.6, 4.3.4.5.7, 4.3.4.5.8, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.13, SR 2.10, SR 2.11, SR 2.12, SR 2.6, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.1, SR 7.1, SR 7.6, A.11.2.6, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.15.2.1, A.15.2.2, A.16.1.4, A.16.1.5, A.16.1.7, A.6.2.1, A.6.2.2, AC-17(1), AU-14(1), AU-10, CM-6(a), IR-5(1), DE.AE-3, DE.AE-5, ID.SC-4, PR.AC-3, PR.PT-1, PR.PT-4, RS.AN-1, RS.AN-4, FAU_GEN.1, Req-10.3, 10.7.3, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215, SRG-OS-000473-GPOS-00218, SRG-OS-000254-GPOS-00095

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    # Correct the form of default kernel command line in GRUB
    if grep -q '^\s*GRUB_CMDLINE_LINUX=.*audit=.*"'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an audit= arg already exists
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)audit=[^[:space:]]\+\(.*\"\)/\1audit=1\2/"  '/etc/default/grub'
    # Add to already existing GRUB_CMDLINE_LINUX parameters
    elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
           # no audit=arg is present, append it
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 audit=1\"/"  '/etc/default/grub'
    # Add GRUB_CMDLINE_LINUX parameters line
    else
           echo "GRUB_CMDLINE_LINUX=\"audit=1\"" >> '/etc/default/grub'
    fi
    grubby --update-kernel=ALL --args=audit=1

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | medium
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Check audit argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=.*audit=' /etc/default/grub
      failed_when: false
      register: argcheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Check audit argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
      failed_when: false
      register: linecheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for  in /etc/audit/audit.rules
      ansible.builtin.lineinfile:
        line: GRUB_CMDLINE_LINUX="audit=1 "
        state: present
        dest: /etc/default/grub
        create: true
        mode: '0644'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc != 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Replace existing audit argument
      replace:
        path: /etc/default/grub
        regexp: audit=\w+
        replace: audit=1
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc == 0 and linecheck.rc == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Add audit argument
      replace:
        path: /etc/default/grub
        regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
        replace: \1 audit=1"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc == 0
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Update grub defaults and the bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="audit=1"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - CJIS-5.4.1.1
      - NIST-800-171-3.3.1
      - NIST-800-53-AC-17(1)
      - NIST-800-53-AU-10
      - NIST-800-53-AU-14(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IR-5(1)
      - PCI-DSS-Req-10.3
      - PCI-DSSv4-10.7.3
      - grub2_audit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

Remediation OSBuild Blueprint snippet ⇲

    [customizations.kernel]
    append = "audit=1"

#### Rule Extend Audit Backlog Limit for the Audit Daemon [ref]

To improve the kernel capacity to queue all log events, even those which occurred prior to the audit daemon, add the argument `audit_backlog_limit=8192` to the default GRUB 2 command line for the Linux operating system. To ensure that `audit_backlog_limit=8192` is added as a kernel command line argument to newly installed kernels, add `audit_backlog_limit=8192` to the default Grub2 command line for Linux operating systems. Modify the line within `/etc/default/grub` as shown below:

    GRUB_CMDLINE_LINUX="... audit_backlog_limit=8192 ..."

Run the following command to update command line for already installed kernels:

    # grubby --update-kernel=ALL --args="audit_backlog_limit=8192"

Rationale: | audit_backlog_limit sets the queue length for audit events awaiting transfer to the audit daemon. Until the audit daemon is up and running, all log messages are stored in this queue. If the queue is overrun during boot process, the action defined by audit failure flag is taken.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_audit_backlog_limit_argument
Identifiers and References | References: CCI-000130, CCI-000135, CCI-000169, CCI-000172, CCI-001849, CCI-002884, CM-6(a), FAU_STG.1, FAU_STG.3, 10.7.2, SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000254-GPOS-00095, SRG-OS-000341-GPOS-00132, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000471-GPOS-00215

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    # Correct the form of default kernel command line in GRUB
    if grep -q '^\s*GRUB_CMDLINE_LINUX=.*audit_backlog_limit=.*"'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an audit_backlog_limit= arg already exists
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)audit_backlog_limit=[^[:space:]]\+\(.*\"\)/\1audit_backlog_limit=8192\2/"  '/etc/default/grub'
    # Add to already existing GRUB_CMDLINE_LINUX parameters
    elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
           # no audit_backlog_limit=arg is present, append it
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 audit_backlog_limit=8192\"/"  '/etc/default/grub'
    # Add GRUB_CMDLINE_LINUX parameters line
    else
           echo "GRUB_CMDLINE_LINUX=\"audit_backlog_limit=8192\"" >> '/etc/default/grub'
    fi
    grubby --update-kernel=ALL --args=audit_backlog_limit=8192

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | medium
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Check audit_backlog_limit argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=.*audit_backlog_limit=' /etc/default/grub
      failed_when: false
      register: argcheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Check audit_backlog_limit argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
      failed_when: false
      register: linecheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for  in /etc/audit/audit.rules
      ansible.builtin.lineinfile:
        line: GRUB_CMDLINE_LINUX="audit_backlog_limit=8192 "
        state: present
        dest: /etc/default/grub
        create: true
        mode: '0644'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc != 0
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Replace existing audit_backlog_limit argument
      replace:
        path: /etc/default/grub
        regexp: audit_backlog_limit=\w+
        replace: audit_backlog_limit=8192
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc == 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Add audit_backlog_limit argument
      replace:
        path: /etc/default/grub
        regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
        replace: \1 audit_backlog_limit=8192"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

    - name: Update grub defaults and the bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="audit_backlog_limit=8192"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-10.7.2
      - grub2_audit_backlog_limit_argument
      - low_disruption
      - low_severity
      - medium_complexity
      - reboot_required
      - restrict_strategy

Remediation OSBuild Blueprint snippet ⇲

    [customizations.kernel]
    append = "audit_backlog_limit=8192"

Group GRUB2 bootloader configuration Group contains 2 groups and 6 rules

[ref] During the boot process, the boot loader is responsible for starting the execution of the kernel and passing options to it. The boot loader allows for the selection of different kernels - possibly on different partitions or media. The default Oracle Linux 7 boot loader for x86 systems is called GRUB2. Options it can pass to the kernel include single-user mode, which provides root access without any authentication, and the ability to disable SELinux. To prevent local users from modifying the boot parameters and endangering security, protect the boot loader configuration with a password and ensure its configuration file's permissions are set properly.

Group Non-UEFI GRUB2 bootloader configuration Group contains 4 rules
[ref] Non-UEFI GRUB2 bootloader configuration

#### Rule Verify /boot/grub2/grub.cfg Group Ownership [ref]

The file `/boot/grub2/grub.cfg` should be group-owned by the `root` group to prevent destruction or modification of the file. To properly set the group owner of `/boot/grub2/grub.cfg`, run the command:

    $ sudo chgrp root /boot/grub2/grub.cfg

Rationale: | The `root` group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_grub2_cfg

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 2.2.6, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    chgrp 0 /boot/grub2/grub.cfg

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_groupowner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Test for existence /boot/grub2/grub.cfg
      stat:
        path: /boot/grub2/grub.cfg
      register: file_exists
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_groupowner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure group owner 0 on /boot/grub2/grub.cfg
      file:
        path: /boot/grub2/grub.cfg
        group: '0'
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - file_exists.stat is defined and file_exists.stat.exists
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_groupowner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Verify /boot/grub2/grub.cfg User Ownership [ref]

The file `/boot/grub2/grub.cfg` should be owned by the `root` user to prevent destruction or modification of the file. To properly set the owner of `/boot/grub2/grub.cfg`, run the command:

    $ sudo chown root /boot/grub2/grub.cfg

Rationale: | Only root should be able to modify important boot parameters.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_grub2_cfg

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, 5.5.2.2, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-7.1, 2.2.6, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    chown 0 /boot/grub2/grub.cfg

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_owner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Test for existence /boot/grub2/grub.cfg
      stat:
        path: /boot/grub2/grub.cfg
      register: file_exists
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_owner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure owner 0 on /boot/grub2/grub.cfg
      file:
        path: /boot/grub2/grub.cfg
        owner: '0'
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - file_exists.stat is defined and file_exists.stat.exists
      tags:
      - CJIS-5.5.2.2
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-7.1
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_owner_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Verify /boot/grub2/grub.cfg Permissions [ref]

File permissions for `/boot/grub2/grub.cfg` should be set to 600. To properly set the permissions of `/boot/grub2/grub.cfg`, run the command:

    $ sudo chmod 600 /boot/grub2/grub.cfg

Rationale: | Proper permissions ensure that only the root user can modify important boot parameters.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_grub2_cfg

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.4.5, CCI-000225, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -d /sys/firmware/efi ] && rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    chmod u-xs,g-xwrs,o-xwrt /boot/grub2/grub.cfg

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Test for existence /boot/grub2/grub.cfg
      stat:
        path: /boot/grub2/grub.cfg
      register: file_exists
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure permission u-xs,g-xwrs,o-xwrt on /boot/grub2/grub.cfg
      file:
        path: /boot/grub2/grub.cfg
        mode: u-xs,g-xwrs,o-xwrt
      when:
      - '"/boot/efi" not in ansible_mounts | map(attribute="mount") | list'
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - file_exists.stat is defined and file_exists.stat.exists
      tags:
      - NIST-800-171-3.4.5
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_grub2_cfg
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Set Boot Loader Password in grub2 [ref]

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password by running the following command:

    # grub2-setpassword

When prompted, enter the password that was selected.
Warning: To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the `grub.cfg` file as the grub2-mkconfig command overwrites this file.

Rationale: | Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_password

Identifiers and References

References: BP28(R17), 1, 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.18.1.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, OL07-00-010482, SV-221700r744071_rule

Group UEFI GRUB2 bootloader configuration Group contains 1 rule
[ref] UEFI GRUB2 bootloader configuration Warning: UEFI generally uses vfat file systems, which does not support Unix-style permissions managed by chmod command. In this case, in order to change file permissions for files within /boot/efi it is necessary to update the mount options in /etc/fstab file and reboot the system.

#### Rule Set the UEFI Boot Loader Password [ref]

The grub2 boot loader should have a superuser account and password protection enabled to protect boot-time settings.
Since plaintext passwords are a security risk, generate a hash for the password by running the following command:

    # grub2-setpassword

When prompted, enter the password that was selected.
Warning: To prevent hard-coded passwords, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above. Also, do NOT manually add the superuser account and password to the `grub.cfg` file as the grub2-mkconfig command overwrites this file.

Rationale: | Password protection on the boot loader configuration ensures users with physical access cannot trivially alter important bootloader settings. These include which kernel to use, and whether to enter single-user mode.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_uefi_password

Identifiers and References

References: BP28(R17), 11, 12, 14, 15, 16, 18, 3, 5, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.4.5, CCI-000213, 164.308(a)(1)(ii)(B), 164.308(a)(7)(i), 164.308(a)(7)(ii)(A), 164.310(a)(1), 164.310(a)(2)(i), 164.310(a)(2)(ii), 164.310(a)(2)(iii), 164.310(b), 164.310(c), 164.310(d)(1), 164.310(d)(2)(iii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), PR.AC-4, PR.AC-6, PR.PT-3, FIA_UAU.1, SRG-OS-000080-GPOS-00048, OL07-00-010491, SV-221702r744074_rule

#### Rule Disable vsyscalls [ref]

To disable use of virtual syscalls, add the argument `vsyscall=none` to the default GRUB 2 command line for the Linux operating system. To ensure that `vsyscall=none` is added as a kernel command line argument to newly installed kernels, add `vsyscall=none` to the default Grub2 command line for Linux operating systems. Modify the line within `/etc/default/grub` as shown below:

    GRUB_CMDLINE_LINUX="... vsyscall=none ..."

Run the following command to update command line for already installed kernels:

    # grubby --update-kernel=ALL --args="vsyscall=none"

Rationale: | Virtual Syscalls provide an opportunity of attack for a user who has control of the return instruction pointer.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_vsyscall_argument
Identifiers and References | References: CCI-001084, CM-7(a), FPT_ASLR_EXT.1, SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q grub2-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # Correct the form of default kernel command line in GRUB
    if grep -q '^\s*GRUB_CMDLINE_LINUX=.*vsyscall=.*"'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an vsyscall= arg already exists
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)vsyscall=[^[:space:]]\+\(.*\"\)/\1vsyscall=none\2/"  '/etc/default/grub'
    # Add to already existing GRUB_CMDLINE_LINUX parameters
    elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
           # no vsyscall=arg is present, append it
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 vsyscall=none\"/"  '/etc/default/grub'
    # Add GRUB_CMDLINE_LINUX parameters line
    else
           echo "GRUB_CMDLINE_LINUX=\"vsyscall=none\"" >> '/etc/default/grub'
    fi
    grubby --update-kernel=ALL --args=vsyscall=none

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | medium
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check vsyscall argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=.*vsyscall=' /etc/default/grub
      failed_when: false
      register: argcheck
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check vsyscall argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
      failed_when: false
      register: linecheck
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for  in /etc/audit/audit.rules
      ansible.builtin.lineinfile:
        line: GRUB_CMDLINE_LINUX="vsyscall=none "
        state: present
        dest: /etc/default/grub
        create: true
        mode: '0644'
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - argcheck.rc != 0 and linecheck.rc != 0
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Replace existing vsyscall argument
      replace:
        path: /etc/default/grub
        regexp: vsyscall=\w+
        replace: vsyscall=none
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - argcheck.rc == 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add vsyscall argument
      replace:
        path: /etc/default/grub
        regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
        replace: \1 vsyscall=none"
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - argcheck.rc != 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Update grub defaults and the bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="vsyscall=none"
      when:
      - '"grub2-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-7(a)
      - grub2_vsyscall_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

Remediation OSBuild Blueprint snippet ⇲

    [customizations.kernel]
    append = "vsyscall=none"

Group Configure Syslog Group contains 3 groups and 3 rules

[ref] The syslog service has been the default Unix logging mechanism for many years. It has a number of downsides, including inconsistent log format, lack of authentication for received messages, and lack of authentication, encryption, or reliable transport for messages sent over a network. However, due to its long history, syslog is a de facto standard which is supported by almost all Unix applications.
In Oracle Linux 7, rsyslog has replaced ksyslogd as the syslog daemon of choice, and it includes some additional security features such as reliable, connection-oriented (i.e. TCP) transmission of logs, the option to log to database formats, and the encryption of log data en route to a central logging server. This section discusses how to configure rsyslog for best effect, and how to use tools provided with the system to maintain and monitor logs.

Group Ensure Proper Configuration of Log Files Group contains 1 rule

[ref] The file `/etc/rsyslog.conf` controls where log message are written. These are controlled by lines called rules, which consist of a selector and an action. These rules are often customized depending on the role of the system, the requirements of the environment, and whatever may enable the administrator to most effectively make use of log data. The default rules in Oracle Linux 7 are:

    *.info;mail.none;authpriv.none;cron.none                /var/log/messages
    authpriv.*                                              /var/log/secure
    mail.*                                                  -/var/log/maillog
    cron.*                                                  /var/log/cron
    *.emerg                                                 *
    uucp,news.crit                                          /var/log/spooler
    local7.*                                                /var/log/boot.log

See the man page `rsyslog.conf(5)` for more information. Note that the `rsyslog` daemon can be configured to use a timestamp format that some log processing programs may not understand. If this occurs, edit the file `/etc/rsyslog.conf` and add or edit the following line:

    $ ActionFileDefaultTemplate RSYSLOG_TraditionalFileFormat

#### Rule Ensure cron Is Logging To Rsyslog [ref]

Cron logging must be implemented to spot intrusions or trace cron job status. If `cron` is not logging to `rsyslog`, it can be implemented by adding the following to the RULES section of `/etc/rsyslog.conf`:

    cron.*                                                  /var/log/cron

Rationale: | Cron logging can be used to trace the successful or unsuccessful execution of cron jobs. It can also be used to spot intrusions into the use of the cron facility by unauthorized and malicious users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_cron_logging

Identifiers and References

References: 1, 14, 15, 16, 3, 5, 6, APO10.01, APO10.03, APO10.04, APO10.05, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA01.01, MEA01.02, MEA01.03, MEA01.04, MEA01.05, MEA02.01, CCI-000366, 4.3.2.6.7, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 6.1, 0988, 1405, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.15.2.1, A.15.2.2, CM-6(a), ID.SC-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000480-GPOS-00227, OL07-00-021100, SV-221750r744083_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! grep -s "^\s*cron\.\*\s*/var/log/cron$" /etc/rsyslog.conf /etc/rsyslog.d/*.conf; then
    	mkdir -p /etc/rsyslog.d
    	echo "cron.*	/var/log/cron" >> /etc/rsyslog.d/cron.conf
    fi

    systemctl restart rsyslog.service

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Group Configure rsyslogd to Accept Remote Messages If Acting as a Log Server Group contains 1 rule
[ref] By default, `rsyslog` does not listen over the network for log messages. If needed, modules can be enabled to allow the rsyslog daemon to receive messages from other systems and for the system thus to act as a log server. If the system is not a log server, then lines concerning these modules should remain commented out.

#### Rule Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server [ref]

The `rsyslog` daemon should not accept remote messages unless the system acts as a log server. To ensure that it is not listening on the network, ensure any of the following lines are not found in `rsyslog` configuration files. If using legacy syntax:

    $ModLoad imtcp
    $InputTCPServerRun port
    $ModLoad imudp
    $UDPServerRun port
    $ModLoad imrelp
    $InputRELPServerRun port

If using RainerScript syntax:

    module(load="imtcp")
    module(load="imudp")
    input(type="imtcp" port="514")
    input(type="imudp" port="514")

Rationale: | Any process which receives messages from the network incurs some risk of receiving malicious messages. This risk can be eliminated for rsyslog by configuring it not to listen on the network.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_nolisten

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, MEA02.01, CCI-000318, CCI-000366, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 4.2.3.4, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.8, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 0988, 1405, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-031010, SV-221836r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    legacy_regex='^\s*\$(((Input(TCP|RELP)|UDP)ServerRun)|ModLoad\s+(imtcp|imudp|imrelp))'
    rainer_regex='^\s*(module|input)\((load|type)="(imtcp|imudp)".*$'

    readarray -t legacy_targets < <(grep -l -E -r "${legacy_regex[@]}" /etc/rsyslog.conf /etc/rsyslog.d/)
    readarray -t rainer_targets < <(grep -l -E -r "${rainer_regex[@]}" /etc/rsyslog.conf /etc/rsyslog.d/)

    config_changed=false
    if [ ${#legacy_targets[@]} -gt 0 ]; then
        for target in "${legacy_targets[@]}"; do
            sed -E -i "/$legacy_regex/ s/^/# /" "$target"
        done
        config_changed=true
    fi

    if [ ${#rainer_targets[@]} -gt 0 ]; then
        for target in "${rainer_targets[@]}"; do
            sed -E -i "/$rainer_regex/ s/^/# /" "$target"
        done
        config_changed=true
    fi

    if $config_changed; then
        systemctl restart rsyslog.service
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Define Rsyslog Config Lines Regex in Legacy Syntax
      ansible.builtin.set_fact:
        rsyslog_listen_legacy_regex: ^\s*\$(((Input(TCP|RELP)|UDP)ServerRun)|ModLoad\s+(imtcp|imudp|imrelp))
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Search for Legacy Config Lines in Rsyslog Main Config File
      ansible.builtin.find:
        paths: /etc
        pattern: rsyslog.conf
        contains: '{{ rsyslog_listen_legacy_regex }}'
      register: rsyslog_listen_legacy_main_file
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Search for Legacy Config Lines in Rsyslog Include Files
      ansible.builtin.find:
        paths: /etc/rsyslog.d/
        pattern: '*.conf'
        contains: '{{ rsyslog_listen_legacy_regex }}'
      register: rsyslog_listen_legacy_include_files
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Assemble List of Config Files With Listen Lines in Legacy Syntax
      ansible.builtin.set_fact:
        rsyslog_legacy_remote_listen_files: '{{ rsyslog_listen_legacy_main_file.files
          | map(attribute=''path'') | list + rsyslog_listen_legacy_include_files.files
          | map(attribute=''path'') | list }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Comment Listen Config Lines Wherever Defined Using Legacy Syntax
      ansible.builtin.replace:
        path: '{{ item }}'
        regexp: '{{ rsyslog_listen_legacy_regex }}'
        replace: '# \1'
      loop: '{{ rsyslog_legacy_remote_listen_files }}'
      register: rsyslog_listen_legacy_comment
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - rsyslog_legacy_remote_listen_files | length > 0
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Define Rsyslog Config Lines Regex in RainerScript Syntax
      ansible.builtin.set_fact:
        rsyslog_listen_rainer_regex: ^\s*(module|input)\((load|type)="(imtcp|imudp)".*$
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Search for RainerScript Config Lines in Rsyslog Main Config File
      ansible.builtin.find:
        paths: /etc
        pattern: rsyslog.conf
        contains: '{{ rsyslog_listen_rainer_regex }}'
      register: rsyslog_rainer_remote_main_file
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Search for RainerScript Config Lines in Rsyslog Include Files
      ansible.builtin.find:
        paths: /etc/rsyslog.d/
        pattern: '*.conf'
        contains: '{{ rsyslog_listen_rainer_regex }}'
      register: rsyslog_rainer_remote_include_files
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Assemble List of Config Files With Listen Lines in RainerScript
      ansible.builtin.set_fact:
        rsyslog_rainer_remote_listen_files: '{{ rsyslog_rainer_remote_main_file.files
          | map(attribute=''path'') | list + rsyslog_rainer_remote_include_files.files
          | map(attribute=''path'') | list }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Comment Listen Config Lines Wherever Defined Using RainerScript
      ansible.builtin.replace:
        path: '{{ item }}'
        regexp: '{{ rsyslog_listen_rainer_regex }}'
        replace: '# \1'
      loop: '{{ rsyslog_rainer_remote_listen_files }}'
      register: rsyslog_listen_rainer_comment
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - rsyslog_rainer_remote_listen_files | length > 0
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

    - name: Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server
        - Restart Rsyslog if Any Line Were Commented Out
      ansible.builtin.service:
        name: rsyslog
        state: restarted
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - rsyslog_listen_legacy_comment is changed or rsyslog_listen_rainer_comment is changed
      tags:
      - DISA-STIG-OL07-00-031010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - rsyslog_nolisten

Group Rsyslog Logs Sent To Remote Host Group contains 1 rule

[ref] If system logs are to be useful in detecting malicious activities, it is necessary to send logs to a remote server. An intruder who has compromised the root account on a system may delete the log entries which indicate that the system was attacked before they are seen by an administrator.
However, it is recommended that logs be stored on the local host in addition to being sent to the loghost, especially if `rsyslog` has been configured to use the UDP protocol to send messages over a network. UDP does not guarantee reliable delivery, and moderately busy sites will lose log messages occasionally, especially in periods of high traffic which may be the result of an attack. In addition, remote `rsyslog` messages are not authenticated in any way by default, so it is easy for an attacker to introduce spurious messages to the central log server. Also, some problems cause loss of network connectivity, which will prevent the sending of messages to the central server. For all of these reasons, it is better to store log messages both centrally and on each host, so that they can be correlated if necessary.

#### Rule Ensure Logs Sent To Remote Host [ref]

To configure rsyslog to send logs to a remote log server, open `/etc/rsyslog.conf` and read and understand the last section of the file, which describes the multiple directives necessary to activate remote logging. Along with these other directives, the system can be configured to forward its logs to a particular log server by adding or correcting one of the following lines, substituting `logcollector` appropriately. The choice of protocol depends on the environment of the system; although TCP and RELP provide more reliable message delivery, they may not be supported in all environments.
To use UDP for log message delivery:

    *.* @logcollector

To use TCP for log message delivery:

    *.* @@logcollector

To use RELP for log message delivery:

    *.* :omrelp:logcollector

There must be a resolvable DNS CNAME or Alias record set to "logcollector" for logs to be sent correctly to the centralized logging utility.
Warning: It is important to configure queues in case the client is sending log messages to a remote server. If queues are not configured, the system will stop functioning when the connection to the remote server is not available. Please consult Rsyslog documentation for more information about configuration of queues. The example configuration which should go into `/etc/rsyslog.conf` can look like the following lines:

    $ActionQueueType LinkedList
    $ActionQueueFileName queuefilename
    $ActionQueueMaxDiskSpace 1g
    $ActionQueueSaveOnShutdown on
    $ActionResumeRetryCount -1

Rationale: | A log server (loghost) receives syslog messages from one or more systems. This data can be used as an additional log source in the event a system is compromised and its local logs are suspect. Forwarding log messages to a remote loghost also provides system administrators with a centralized place to view the status of multiple hosts within the enterprise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_rsyslog_remote_loghost

Identifiers and References

References: BP28(R7), NT28(R43), NT12(R5), 1, 13, 14, 15, 16, 2, 3, 5, 6, APO11.04, APO13.01, BAI03.05, BAI04.04, DSS05.04, DSS05.07, MEA02.01, CCI-000366, CCI-001348, CCI-000136, CCI-001851, 164.308(a)(1)(ii)(D), 164.308(a)(5)(ii)(B), 164.308(a)(5)(ii)(C), 164.308(a)(6)(ii), 164.308(a)(8), 164.310(d)(2)(iii), 164.312(b), 164.314(a)(2)(i)(C), 164.314(a)(2)(iii), 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, SR 7.1, SR 7.2, 0988, 1405, A.12.1.3, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.17.2.1, CIP-003-8 R5.2, CIP-004-6 R3.3, CM-6(a), AU-4(1), AU-9(2), PR.DS-4, PR.PT-1, FAU_GEN.1.1.c, SRG-OS-000479-GPOS-00224, SRG-OS-000480-GPOS-00227, SRG-OS-000342-GPOS-00133, OL07-00-031000, SV-221835r917854_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    rsyslog_remote_loghost_address='logcollector'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^\*\.\*")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "@@$rsyslog_remote_loghost_address"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^\*\.\*\\>" "/etc/rsyslog.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^\*\.\*\\>.*/$escaped_formatted_output/gi" "/etc/rsyslog.conf"
    else
        if [[ -s "/etc/rsyslog.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/rsyslog.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/rsyslog.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/rsyslog.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value rsyslog_remote_loghost_address # promote to variable
      set_fact:
        rsyslog_remote_loghost_address: !!str logcollector
      tags:
        - always

    - name: Set rsyslog remote loghost
      lineinfile:
        dest: /etc/rsyslog.conf
        regexp: ^\*\.\*
        line: '*.* @@{{ rsyslog_remote_loghost_address }}'
        create: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-031000
      - NIST-800-53-AU-4(1)
      - NIST-800-53-AU-9(2)
      - NIST-800-53-CM-6(a)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - rsyslog_remote_loghost

Group Network Configuration and Firewalls Group contains 13 groups and 35 rules

[ref] Most systems must be connected to a network of some sort, and this brings with it the substantial risk of network attack. This section discusses the security impact of decisions about networking which must be made when configuring a system.
This section also discusses firewalls, network access controls, and other network security frameworks, which allow system-level rules to be written that can limit an attackers' ability to connect to your system. These rules can specify that network traffic should be allowed or denied from certain IP addresses, hosts, and networks. The rules can also specify which of the system's network services are available to particular hosts or networks.

Group firewalld Group contains 2 groups and 2 rules

[ref] The dynamic firewall daemon `firewalld` provides a dynamically managed firewall with support for network “zones” to assign a level of trust to a network and its associated connections and interfaces. It has support for IPv4 and IPv6 firewall settings. It supports Ethernet bridges and has a separation of runtime and permanent configuration options. It also has an interface for services or applications to add firewall rules directly.
A graphical configuration tool, `firewall-config`, is used to configure `firewalld`, which in turn uses `iptables` tool to communicate with `Netfilter` in the kernel which implements packet filtering.
The firewall service provided by `firewalld` is dynamic rather than static because changes to the configuration can be made at anytime and are immediately implemented. There is no need to save or apply the changes. No unintended disruption of existing network connections occurs as no part of the firewall has to be reloaded.

Group Inspect and Activate Default firewalld Rules Group contains 1 rule

[ref] Firewalls can be used to separate networks into different zones based on the level of trust the user has decided to place on the devices and traffic within that network. `NetworkManager` informs firewalld to which zone an interface belongs. An interface's assigned zone can be changed by `NetworkManager` or via the `firewall-config` tool.
The zone settings in `/etc/firewalld/` are a range of preset settings which can be quickly applied to a network interface. These are the zones provided by firewalld sorted according to the default trust level of the zones from untrusted to trusted:

- `drop`

  Any incoming network packets are dropped, there is no reply. Only outgoing network connections are possible.

- `block`

  Any incoming network connections are rejected with an `icmp-host-prohibited` message for IPv4 and `icmp6-adm-prohibited` for IPv6. Only network connections initiated from within the system are possible.

- `public`

  For use in public areas. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.

- `external`

  For use on external networks with masquerading enabled especially for routers. You do not trust the other computers on the network to not harm your computer. Only selected incoming connections are accepted.

- `dmz`

  For computers in your demilitarized zone that are publicly-accessible with limited access to your internal network. Only selected incoming connections are accepted.

- `work`

  For use in work areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.

- `home`

  For use in home areas. You mostly trust the other computers on networks to not harm your computer. Only selected incoming connections are accepted.

- `internal`

  For use on internal networks. You mostly trust the other computers on the networks to not harm your computer. Only selected incoming connections are accepted.

- `trusted`

  All network connections are accepted.

It is possible to designate one of these zones to be the default zone. When interface connections are added to `NetworkManager`, they are assigned to the default zone. On installation, the default zone in firewalld is set to be the public zone.
To find out all the settings of a zone, for example the `public zone,` enter the following command as root:

    # firewall-cmd --zone=public --list-all

Example output of this command might look like the following:

    # firewall-cmd --zone=public --list-all
    public
      interfaces:
      services: mdns dhcpv6-client ssh
      ports:
      forward-ports:
      icmp-blocks: source-quench

To view the network zones currently active, enter the following command as root:

    # firewall-cmd --get-service

The following listing displays the result of this command on common Oracle Linux 7 system:

    # firewall-cmd --get-service
    amanda-client bacula bacula-client dhcp dhcpv6 dhcpv6-client dns ftp
    high-availability http https imaps ipp ipp-client ipsec kerberos kpasswd
    ldap ldaps libvirt libvirt-tls mdns mountd ms-wbt mysql nfs ntp openvpn
    pmcd pmproxy pmwebapi pmwebapis pop3s postgresql proxy-dhcp radius rpc-bind
    samba samba-client smtp ssh telnet tftp tftp-client transmission-client
    vnc-server wbem-https

Finally to view the network zones that will be active after the next firewalld service reload, enter the following command as root:

    # firewall-cmd --get-service --permanent

#### Rule Verify firewalld Enabled [ref]

The `firewalld` service can be enabled with the following command:

    $ sudo systemctl enable firewalld.service

Rationale: | Access control methods provide the ability to enhance system security posture by restricting services and known good IP addresses and address ranges. This prevents connections from unknown hosts and protocols.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_firewalld_enabled

Identifiers and References

References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.3, 3.4.7, CCI-000366, CCI-000382, CCI-002314, 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-003-8 R4, CIP-003-8 R5, CIP-004-6 R3, AC-4, CM-7(b), CA-3(5), SC-7(21), CM-6(a), PR.IP-1, FMT_SMF_EXT.1, 1.2.1, SRG-OS-000096-GPOS-00050, SRG-OS-000297-GPOS-00115, SRG-OS-000480-GPOS-00227, SRG-OS-000480-GPOS-00231, SRG-OS-000480-GPOS-00232, OL07-00-040520, SV-221868r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q firewalld; }; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" unmask 'firewalld.service'
    "$SYSTEMCTL_EXEC" start 'firewalld.service'
    "$SYSTEMCTL_EXEC" enable 'firewalld.service'

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-040520
      - NIST-800-171-3.1.3
      - NIST-800-171-3.4.7
      - NIST-800-53-AC-4
      - NIST-800-53-CA-3(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(21)
      - PCI-DSSv4-1.2.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_firewalld_enabled

    - name: Enable service firewalld
      block:

      - name: Gather the package facts
        package_facts:
          manager: auto

      - name: Enable service firewalld
        systemd:
          name: firewalld
          enabled: 'yes'
          state: started
          masked: 'no'
        when:
        - '"firewalld" in ansible_facts.packages'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"firewalld" in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-040520
      - NIST-800-171-3.1.3
      - NIST-800-171-3.4.7
      - NIST-800-53-AC-4
      - NIST-800-53-CA-3(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(21)
      - PCI-DSSv4-1.2.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_firewalld_enabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    enabled = ["firewalld"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include enable_firewalld

    class enable_firewalld {
      service {'firewalld':
        enable => true,
        ensure => 'running',
      }
    }

Group Strengthen the Default Ruleset Group contains 1 rule

[ref] The default rules can be strengthened. The system scripts that activate the firewall rules expect them to be defined in configuration files under the `/etc/firewalld/services` and `/etc/firewalld/zones` directories.
The following recommendations describe how to strengthen the default ruleset configuration file. An alternative to editing this configuration file is to create a shell script that makes calls to the `firewall-cmd` program to load in rules under the `/etc/firewalld/services` and `/etc/firewalld/zones` directories.
Instructions apply to both unless otherwise noted. Language and address conventions for regular firewalld rules are used throughout this section.
Warning: The program `firewall-config` allows additional services to penetrate the default firewall rules and automatically adjusts the `firewalld` ruleset(s).

#### Rule Set Default firewalld Zone for Incoming Packets [ref]

To set the default zone to `drop` for the built-in default zone which processes incoming IPv4 and IPv6 packets, modify the following line in `/etc/firewalld/firewalld.conf` to be:

    DefaultZone=drop

Warning: To prevent denying any access to the system, automatic remediation of this control is not available. Remediation must be automated as a component of machine provisioning, or followed manually as outlined above.

Rationale: | In `firewalld` the default zone is applied only after all the applicable rules in the table are examined for a match. Setting the default zone to `drop` implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_set_firewalld_default_zone

Identifiers and References

References: 11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.3, 3.4.7, 3.13.6, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 1416, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CA-3(5), CM-7(b), SC-7(23), CM-6(a), PR.IP-1, PR.PT-3, FMT_MOF_EXT.1, Req-1.4, 1.3.1, 1.5.1, SRG-OS-000480-GPOS-00227

Group IPSec Support Group contains 1 rule
[ref] Support for Internet Protocol Security (IPsec) is provided with Libreswan.

#### Rule Verify Any Configured IPSec Tunnel Connections [ref]

Libreswan provides an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. As such, IPsec can be used to circumvent certain network requirements such as filtering. Verify that if any IPsec connection (`conn`) configured in `/etc/ipsec.conf` and `/etc/ipsec.d` exists is an approved organizational connection.
Warning: Automatic remediation of this control is not available due to the unique requirements of each system.

Rationale: | IP tunneling mechanisms can be used to bypass network filtering.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_libreswan_approved_tunnels

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, CCI-000336, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), MA-4(6), CM-6(a), AC-4, SC-8, DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040820, SV-221893r603260_rule

Group IPv6 Group contains 2 groups and 10 rules
[ref] The system includes support for Internet Protocol version 6. A major and often-mentioned improvement over IPv4 is its enormous increase in the number of available addresses. Another important feature is its support for automatic configuration of many network settings.
Group Disable Support for IPv6 Unless Needed Group contains 2 rules
[ref] Despite configuration that suggests support for IPv6 has been disabled, link-local IPv6 address auto-configuration occurs even when only an IPv4 address is assigned. The only way to effectively prevent execution of the IPv6 networking stack is to instruct the system not to activate the IPv6 kernel module.

#### Rule Disable Support for RPC IPv6 [ref]

RPC services for NFSv4 try to load transport modules for `udp6` and `tcp6` by default, even if IPv6 has been disabled in `/etc/modprobe.d`. To prevent RPC services such as `rpc.mountd` from attempting to start IPv6 network listeners, remove or comment out the following two lines in `/etc/netconfig`:

    udp6       tpi_clts      v     inet6    udp     -       -
    tcp6       tpi_cots_ord  v     inet6    tcp     -       -

Rationale: |
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_network_ipv6_disable_rpc

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

    # Drop 'tcp6' and 'udp6' entries from /etc/netconfig to prevent RPC
    # services for NFSv4 from attempting to start IPv6 network listeners
    declare -a IPV6_RPC_ENTRIES=("tcp6" "udp6")

    for rpc_entry in "${IPV6_RPC_ENTRIES[@]}"
    do
    	sed -i "/^${rpc_entry}[[:space:]]\\+tpi\\_.*inet6.*/d" /etc/netconfig
    done

#### Rule Disable IPv6 Addressing on All IPv6 Interfaces [ref]

To disable support for (`ipv6`) addressing on all interface add the following line to `/etc/sysctl.d/ipv6.conf` (or another file in `/etc/sysctl.d`):

    net.ipv6.conf.all.disable_ipv6 = 1

This disables IPv6 on all network interfaces as other services and system functionality require the IPv6 stack loaded to work.

Rationale: | Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_disable_ipv6

Identifiers and References

References: BP28(R13), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.all.disable_ipv6 from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.disable_ipv6.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.all.disable_ipv6" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for net.ipv6.conf.all.disable_ipv6
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.all.disable_ipv6="1"

    #
    # If net.ipv6.conf.all.disable_ipv6 present in /etc/sysctl.conf, change value to "1"
    #	else, add "net.ipv6.conf.all.disable_ipv6 = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.disable_ipv6")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.disable_ipv6\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.disable_ipv6\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.all.disable_ipv6.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_disable_ipv6

    - name: Comment out any occurrences of net.ipv6.conf.all.disable_ipv6 from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.all.disable_ipv6
        replace: '#net.ipv6.conf.all.disable_ipv6'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_disable_ipv6

    - name: Ensure sysctl net.ipv6.conf.all.disable_ipv6 is set to 1
      sysctl:
        name: net.ipv6.conf.all.disable_ipv6
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_disable_ipv6

Group Configure IPv6 Settings if Necessary Group contains 8 rules
[ref] A major feature of IPv6 is the extent to which systems implementing it can automatically configure their networking devices using information from the network. From a security perspective, manually configuring important configuration information is preferable to accepting it from the network in an unauthenticated fashion.

#### Rule Use Privacy Extensions for Address [ref]

To introduce randomness into the automatic generation of IPv6 addresses, add or correct the following line in `/etc/sysconfig/network-scripts/ifcfg-interface`:

    IPV6_PRIVACY=rfc3041

Automatically-generated IPv6 addresses are based on the underlying hardware (e.g. Ethernet) address, and so it becomes possible to track a piece of hardware over its lifetime using its traffic. If it is important for a system's IP address to not trivially reveal its hardware address, this setting should be applied.

Rationale: |
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_network_ipv6_privacy_extensions
Identifiers and References | References: 3.1.20, CCI-000366

Remediation Shell script ⇲

    # enable randomness in ipv6 address generation
    for interface in /etc/sysconfig/network-scripts/ifcfg-*
    do
        echo "IPV6_PRIVACY=rfc3041" >> $interface
    done

#### Rule Configure Accepting Router Advertisements on All IPv6 Interfaces [ref]

To set the runtime status of the `net.ipv6.conf.all.accept_ra` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.all.accept_ra=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.all.accept_ra = 0

Rationale: | An illicit router advertisement message could result in a man-in-the-middle attack.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_ra

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.all.accept_ra from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_ra.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.all.accept_ra" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_all_accept_ra_value='0'

    #
    # Set runtime for net.ipv6.conf.all.accept_ra
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_ra="$sysctl_net_ipv6_conf_all_accept_ra_value"

    #
    # If net.ipv6.conf.all.accept_ra present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.all.accept_ra = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_ra")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_ra_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_ra\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_ra\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.all.accept_ra.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_ra

    - name: Comment out any occurrences of net.ipv6.conf.all.accept_ra from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.all.accept_ra
        replace: '#net.ipv6.conf.all.accept_ra'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_ra
    - name: XCCDF Value sysctl_net_ipv6_conf_all_accept_ra_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_all_accept_ra_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.all.accept_ra is set
      sysctl:
        name: net.ipv6.conf.all.accept_ra
        value: '{{ sysctl_net_ipv6_conf_all_accept_ra_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_ra

#### Rule Disable Accepting ICMP Redirects for All IPv6 Interfaces [ref]

To set the runtime status of the `net.ipv6.conf.all.accept_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.all.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.all.accept_redirects = 0

Rationale: | An illicit ICMP redirect message could result in a man-in-the-middle attack.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_redirects

Identifiers and References

References: BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.all.accept_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.all.accept_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_all_accept_redirects_value='0'

    #
    # Set runtime for net.ipv6.conf.all.accept_redirects
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_redirects="$sysctl_net_ipv6_conf_all_accept_redirects_value"

    #
    # If net.ipv6.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.all.accept_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.all.accept_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_redirects

    - name: Comment out any occurrences of net.ipv6.conf.all.accept_redirects from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.all.accept_redirects
        replace: '#net.ipv6.conf.all.accept_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_redirects
    - name: XCCDF Value sysctl_net_ipv6_conf_all_accept_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_all_accept_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.all.accept_redirects is set
      sysctl:
        name: net.ipv6.conf.all.accept_redirects
        value: '{{ sysctl_net_ipv6_conf_all_accept_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_redirects

#### Rule Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv6 Interfaces [ref]

To set the runtime status of the `net.ipv6.conf.all.accept_source_route` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.all.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router.
Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_accept_source_route

Identifiers and References

References: BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040830, SV-221894r880666_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.all.accept_source_route from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.accept_source_route.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.all.accept_source_route" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_all_accept_source_route_value='0'

    #
    # Set runtime for net.ipv6.conf.all.accept_source_route
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.all.accept_source_route="$sysctl_net_ipv6_conf_all_accept_source_route_value"

    #
    # If net.ipv6.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.all.accept_source_route = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.accept_source_route")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_accept_source_route_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.all.accept_source_route.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040830
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_source_route

    - name: Comment out any occurrences of net.ipv6.conf.all.accept_source_route from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.all.accept_source_route
        replace: '#net.ipv6.conf.all.accept_source_route'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040830
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_source_route
    - name: XCCDF Value sysctl_net_ipv6_conf_all_accept_source_route_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_all_accept_source_route_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.all.accept_source_route is set
      sysctl:
        name: net.ipv6.conf.all.accept_source_route
        value: '{{ sysctl_net_ipv6_conf_all_accept_source_route_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040830
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_accept_source_route

#### Rule Disable Kernel Parameter for IPv6 Forwarding [ref]

To set the runtime status of the `net.ipv6.conf.all.forwarding` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.all.forwarding=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.all.forwarding = 0

Rationale: | IP forwarding permits the kernel to forward packets from one network interface to another. The ability to forward packets between two networks is only appropriate for systems acting as routers.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_all_forwarding

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.all.forwarding from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.all.forwarding.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.all.forwarding" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_all_forwarding_value='0'

    #
    # Set runtime for net.ipv6.conf.all.forwarding
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.all.forwarding="$sysctl_net_ipv6_conf_all_forwarding_value"

    #
    # If net.ipv6.conf.all.forwarding present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.all.forwarding = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.all.forwarding")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_all_forwarding_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.all.forwarding\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.all.forwarding\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.all.forwarding.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_forwarding

    - name: Comment out any occurrences of net.ipv6.conf.all.forwarding from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.all.forwarding
        replace: '#net.ipv6.conf.all.forwarding'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_forwarding
    - name: XCCDF Value sysctl_net_ipv6_conf_all_forwarding_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_all_forwarding_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.all.forwarding is set
      sysctl:
        name: net.ipv6.conf.all.forwarding
        value: '{{ sysctl_net_ipv6_conf_all_forwarding_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_all_forwarding

#### Rule Disable Accepting Router Advertisements on all IPv6 Interfaces by Default [ref]

To set the runtime status of the `net.ipv6.conf.default.accept_ra` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.default.accept_ra=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.default.accept_ra = 0

Rationale: | An illicit router advertisement message could result in a man-in-the-middle attack.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_ra

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.default.accept_ra from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_ra.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.default.accept_ra" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_default_accept_ra_value='0'

    #
    # Set runtime for net.ipv6.conf.default.accept_ra
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_ra="$sysctl_net_ipv6_conf_default_accept_ra_value"

    #
    # If net.ipv6.conf.default.accept_ra present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.default.accept_ra = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_ra")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_ra_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_ra\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_ra\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.default.accept_ra.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_ra

    - name: Comment out any occurrences of net.ipv6.conf.default.accept_ra from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.default.accept_ra
        replace: '#net.ipv6.conf.default.accept_ra'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_ra
    - name: XCCDF Value sysctl_net_ipv6_conf_default_accept_ra_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_default_accept_ra_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.default.accept_ra is set
      sysctl:
        name: net.ipv6.conf.default.accept_ra
        value: '{{ sysctl_net_ipv6_conf_default_accept_ra_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_ra

#### Rule Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv6 Interfaces [ref]

To set the runtime status of the `net.ipv6.conf.default.accept_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.default.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.default.accept_redirects = 0

Rationale: | An illicit ICMP redirect message could result in a man-in-the-middle attack.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_redirects

Identifiers and References

References: BP28(R22), 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.default.accept_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.default.accept_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_default_accept_redirects_value='0'

    #
    # Set runtime for net.ipv6.conf.default.accept_redirects
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_redirects="$sysctl_net_ipv6_conf_default_accept_redirects_value"

    #
    # If net.ipv6.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.default.accept_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.default.accept_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_redirects

    - name: Comment out any occurrences of net.ipv6.conf.default.accept_redirects from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.default.accept_redirects
        replace: '#net.ipv6.conf.default.accept_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_redirects
    - name: XCCDF Value sysctl_net_ipv6_conf_default_accept_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_default_accept_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.default.accept_redirects is set
      sysctl:
        name: net.ipv6.conf.default.accept_redirects
        value: '{{ sysctl_net_ipv6_conf_default_accept_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_redirects

#### Rule Disable Kernel Parameter for Accepting Source-Routed Packets on IPv6 Interfaces by Default [ref]

To set the runtime status of the `net.ipv6.conf.default.accept_source_route` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv6.conf.default.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv6.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv6 forwarding is enabled and the system is functioning as a router. Accepting source-routed packets in the IPv6 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv6_conf_default_accept_source_route

Identifiers and References

References: BP28(R22), 1, 12, 13, 14, 15, 16, 18, 4, 6, 8, 9, APO01.06, APO13.01, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), CM-6(b), CM-6.1(iv), DE.AE-1, ID.AM-3, PR.AC-5, PR.DS-5, PR.PT-4, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv6.conf.default.accept_source_route from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv6.conf.default.accept_source_route.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv6.conf.default.accept_source_route" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv6_conf_default_accept_source_route_value='0'

    #
    # Set runtime for net.ipv6.conf.default.accept_source_route
    #
    /sbin/sysctl -q -n -w net.ipv6.conf.default.accept_source_route="$sysctl_net_ipv6_conf_default_accept_source_route_value"

    #
    # If net.ipv6.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv6.conf.default.accept_source_route = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv6.conf.default.accept_source_route")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv6_conf_default_accept_source_route_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv6.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv6.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv6.conf.default.accept_source_route.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_source_route

    - name: Comment out any occurrences of net.ipv6.conf.default.accept_source_route from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv6.conf.default.accept_source_route
        replace: '#net.ipv6.conf.default.accept_source_route'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_source_route
    - name: XCCDF Value sysctl_net_ipv6_conf_default_accept_source_route_value # promote to variable
      set_fact:
        sysctl_net_ipv6_conf_default_accept_source_route_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv6.conf.default.accept_source_route is set
      sysctl:
        name: net.ipv6.conf.default.accept_source_route
        value: '{{ sysctl_net_ipv6_conf_default_accept_source_route_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-6.1(iv)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv6_conf_default_accept_source_route

Group Kernel Parameters Which Affect Networking Group contains 2 groups and 16 rules
[ref] The `sysctl` utility is used to set parameters which affect the operation of the Linux kernel. Kernel parameters which affect networking and have security implications are described here.
Group Network Related Kernel Runtime Parameters for Hosts and Routers Group contains 13 rules
[ref] Certain kernel parameters should be set for systems which are acting as either hosts or routers to improve the system's ability defend against certain types of IPv4 protocol attacks.

#### Rule Disable Accepting ICMP Redirects for All IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.accept_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.accept_redirects = 0

Rationale: | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required."
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, 5.10.1.1, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, CCI-001503, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, SRG-OS-000480-GPOS-00227, OL07-00-040641, SV-221879r880654_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.accept_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.accept_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_all_accept_redirects_value='0'

    #
    # Set runtime for net.ipv4.conf.all.accept_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.accept_redirects="$sysctl_net_ipv4_conf_all_accept_redirects_value"

    #
    # If net.ipv4.conf.all.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.all.accept_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.accept_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040641
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_redirects

    - name: Comment out any occurrences of net.ipv4.conf.all.accept_redirects from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.accept_redirects
        replace: '#net.ipv4.conf.all.accept_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040641
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_redirects
    - name: XCCDF Value sysctl_net_ipv4_conf_all_accept_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_all_accept_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.all.accept_redirects is set
      sysctl:
        name: net.ipv4.conf.all.accept_redirects
        value: '{{ sysctl_net_ipv4_conf_all_accept_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040641
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_redirects

#### Rule Disable Kernel Parameter for Accepting Source-Routed Packets on all IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.accept_source_route` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures. This requirement applies only to the forwarding of source-routerd traffic, such as when IPv4 forwarding is enabled and the system is functioning as a router.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_accept_source_route

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040610, SV-221873r880636_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.accept_source_route from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.accept_source_route.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.accept_source_route" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_all_accept_source_route_value='0'

    #
    # Set runtime for net.ipv4.conf.all.accept_source_route
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.accept_source_route="$sysctl_net_ipv4_conf_all_accept_source_route_value"

    #
    # If net.ipv4.conf.all.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.all.accept_source_route = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.accept_source_route")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_accept_source_route_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.accept_source_route.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040610
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_source_route

    - name: Comment out any occurrences of net.ipv4.conf.all.accept_source_route from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.accept_source_route
        replace: '#net.ipv4.conf.all.accept_source_route'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040610
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_source_route
    - name: XCCDF Value sysctl_net_ipv4_conf_all_accept_source_route_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_all_accept_source_route_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.all.accept_source_route is set
      sysctl:
        name: net.ipv4.conf.all.accept_source_route
        value: '{{ sysctl_net_ipv4_conf_all_accept_source_route_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040610
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_accept_source_route

#### Rule Enable Kernel Parameter to Log Martian Packets on all IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.log_martians` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.log_martians=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.log_martians = 1

Rationale: | The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_log_martians

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000126, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), SC-5(3)(a), DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.log_martians from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.log_martians.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.log_martians" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_all_log_martians_value='1'

    #
    # Set runtime for net.ipv4.conf.all.log_martians
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.log_martians="$sysctl_net_ipv4_conf_all_log_martians_value"

    #
    # If net.ipv4.conf.all.log_martians present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.all.log_martians = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.log_martians")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_log_martians_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.log_martians\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.log_martians\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.log_martians.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_all_log_martians
      - unknown_severity

    - name: Comment out any occurrences of net.ipv4.conf.all.log_martians from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.log_martians
        replace: '#net.ipv4.conf.all.log_martians'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_all_log_martians
      - unknown_severity
    - name: XCCDF Value sysctl_net_ipv4_conf_all_log_martians_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_all_log_martians_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.all.log_martians is set
      sysctl:
        name: net.ipv4.conf.all.log_martians
        value: '{{ sysctl_net_ipv4_conf_all_log_martians_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_all_log_martians
      - unknown_severity

#### Rule Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.rp_filter` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.rp_filter=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.rp_filter = 1

Rationale: | Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_rp_filter

Identifiers and References

References: BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227, OL07-00-040611, SV-221874r880639_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.rp_filter from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.rp_filter.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.rp_filter" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_all_rp_filter_value='1'

    #
    # Set runtime for net.ipv4.conf.all.rp_filter
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.rp_filter="$sysctl_net_ipv4_conf_all_rp_filter_value"

    #
    # If net.ipv4.conf.all.rp_filter present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.all.rp_filter = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.rp_filter")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_rp_filter_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.rp_filter\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.rp_filter.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040611
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_rp_filter

    - name: Comment out any occurrences of net.ipv4.conf.all.rp_filter from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.rp_filter
        replace: '#net.ipv4.conf.all.rp_filter'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040611
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_rp_filter
    - name: XCCDF Value sysctl_net_ipv4_conf_all_rp_filter_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_all_rp_filter_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.all.rp_filter is set
      sysctl:
        name: net.ipv4.conf.all.rp_filter
        value: '{{ sysctl_net_ipv4_conf_all_rp_filter_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040611
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_rp_filter

#### Rule Disable Kernel Parameter for Accepting Secure ICMP Redirects on all IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.secure_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.secure_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.secure_redirects = 0

Rationale: | Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_secure_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001503, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.secure_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.secure_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.secure_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_all_secure_redirects_value='0'

    #
    # Set runtime for net.ipv4.conf.all.secure_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.secure_redirects="$sysctl_net_ipv4_conf_all_secure_redirects_value"

    #
    # If net.ipv4.conf.all.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.all.secure_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.secure_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_all_secure_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.secure_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_secure_redirects

    - name: Comment out any occurrences of net.ipv4.conf.all.secure_redirects from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.secure_redirects
        replace: '#net.ipv4.conf.all.secure_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_secure_redirects
    - name: XCCDF Value sysctl_net_ipv4_conf_all_secure_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_all_secure_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.all.secure_redirects is set
      sysctl:
        name: net.ipv4.conf.all.secure_redirects
        value: '{{ sysctl_net_ipv4_conf_all_secure_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_secure_redirects

#### Rule Disable Kernel Parameter for Accepting ICMP Redirects by Default on IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.default.accept_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.accept_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.accept_redirects = 0

Rationale: | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages modify the host's route table and are unauthenticated. An illicit ICMP redirect message could result in a man-in-the-middle attack. This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless absolutely required.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.3, SRG-OS-000480-GPOS-00227, OL07-00-040640, SV-221878r880651_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.accept_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.accept_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_default_accept_redirects_value='0'

    #
    # Set runtime for net.ipv4.conf.default.accept_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.accept_redirects="$sysctl_net_ipv4_conf_default_accept_redirects_value"

    #
    # If net.ipv4.conf.default.accept_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.default.accept_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.accept_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040640
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_redirects

    - name: Comment out any occurrences of net.ipv4.conf.default.accept_redirects from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.accept_redirects
        replace: '#net.ipv4.conf.default.accept_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040640
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_redirects
    - name: XCCDF Value sysctl_net_ipv4_conf_default_accept_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_default_accept_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.default.accept_redirects is set
      sysctl:
        name: net.ipv4.conf.default.accept_redirects
        value: '{{ sysctl_net_ipv4_conf_default_accept_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040640
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_redirects

#### Rule Disable Kernel Parameter for Accepting Source-Routed Packets on IPv4 Interfaces by Default [ref]

To set the runtime status of the `net.ipv4.conf.default.accept_source_route` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.accept_source_route=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.accept_source_route = 0

Rationale:

Source-routed packets allow the source of the packet to suggest routers forward the packet along a different path than configured on the router, which can be used to bypass network security measures.
Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required, such as when IPv4 forwarding is enabled and the system is legitimately functioning as a router.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_accept_source_route

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040620, SV-221876r880645_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.accept_source_route from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.accept_source_route.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.accept_source_route" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_default_accept_source_route_value='0'

    #
    # Set runtime for net.ipv4.conf.default.accept_source_route
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.accept_source_route="$sysctl_net_ipv4_conf_default_accept_source_route_value"

    #
    # If net.ipv4.conf.default.accept_source_route present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.default.accept_source_route = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.accept_source_route")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_accept_source_route_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.accept_source_route\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.accept_source_route\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.accept_source_route.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040620
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_source_route

    - name: Comment out any occurrences of net.ipv4.conf.default.accept_source_route from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.accept_source_route
        replace: '#net.ipv4.conf.default.accept_source_route'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040620
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_source_route
    - name: XCCDF Value sysctl_net_ipv4_conf_default_accept_source_route_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_default_accept_source_route_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.default.accept_source_route is set
      sysctl:
        name: net.ipv4.conf.default.accept_source_route
        value: '{{ sysctl_net_ipv4_conf_default_accept_source_route_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040620
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_accept_source_route

#### Rule Enable Kernel Paremeter to Log Martian Packets on all IPv4 Interfaces by Default [ref]

To set the runtime status of the `net.ipv4.conf.default.log_martians` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.log_martians=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.log_martians = 1

Rationale: | The presence of "martian" packets (which have impossible addresses) as well as spoofed packets, source-routed packets, and redirects could be a sign of nefarious network activity. Logging these packets enables this activity to be detected.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_log_martians

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.04, DSS03.05, DSS05.02, DSS05.03, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000126, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.11.2.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), SC-5(3)(a), DE.CM-1, PR.AC-3, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.log_martians from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.log_martians.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.log_martians" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_default_log_martians_value='1'

    #
    # Set runtime for net.ipv4.conf.default.log_martians
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.log_martians="$sysctl_net_ipv4_conf_default_log_martians_value"

    #
    # If net.ipv4.conf.default.log_martians present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.default.log_martians = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.log_martians")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_log_martians_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.log_martians\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.log_martians\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.log_martians.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_default_log_martians
      - unknown_severity

    - name: Comment out any occurrences of net.ipv4.conf.default.log_martians from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.log_martians
        replace: '#net.ipv4.conf.default.log_martians'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_default_log_martians
      - unknown_severity
    - name: XCCDF Value sysctl_net_ipv4_conf_default_log_martians_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_default_log_martians_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.default.log_martians is set
      sysctl:
        name: net.ipv4.conf.default.log_martians
        value: '{{ sysctl_net_ipv4_conf_default_log_martians_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(3)(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_conf_default_log_martians
      - unknown_severity

#### Rule Enable Kernel Parameter to Use Reverse Path Filtering on all IPv4 Interfaces by Default [ref]

To set the runtime status of the `net.ipv4.conf.default.rp_filter` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.rp_filter=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.rp_filter = 1

Rationale: | Enabling reverse path filtering drops packets with source addresses that should not have been able to be received on the interface they were received on. It should not be used on systems which are routers for complicated networks, but is helpful for end hosts and routers serving small networks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_rp_filter

Identifiers and References

References: BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, SRG-OS-000480-GPOS-00227, OL07-00-040612, SV-221875r880642_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.rp_filter from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.rp_filter.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.rp_filter" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_default_rp_filter_value='1'

    #
    # Set runtime for net.ipv4.conf.default.rp_filter
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.rp_filter="$sysctl_net_ipv4_conf_default_rp_filter_value"

    #
    # If net.ipv4.conf.default.rp_filter present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.default.rp_filter = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.rp_filter")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_rp_filter_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.rp_filter\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.rp_filter\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.rp_filter.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040612
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_rp_filter

    - name: Comment out any occurrences of net.ipv4.conf.default.rp_filter from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.rp_filter
        replace: '#net.ipv4.conf.default.rp_filter'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040612
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_rp_filter
    - name: XCCDF Value sysctl_net_ipv4_conf_default_rp_filter_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_default_rp_filter_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.default.rp_filter is set
      sysctl:
        name: net.ipv4.conf.default.rp_filter
        value: '{{ sysctl_net_ipv4_conf_default_rp_filter_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040612
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_rp_filter

#### Rule Configure Kernel Parameter for Accepting Secure Redirects By Default [ref]

To set the runtime status of the `net.ipv4.conf.default.secure_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.secure_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.secure_redirects = 0

Rationale: | Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_secure_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-001551, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.secure_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.secure_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.secure_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_conf_default_secure_redirects_value='0'

    #
    # Set runtime for net.ipv4.conf.default.secure_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.secure_redirects="$sysctl_net_ipv4_conf_default_secure_redirects_value"

    #
    # If net.ipv4.conf.default.secure_redirects present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.conf.default.secure_redirects = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.secure_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_conf_default_secure_redirects_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.secure_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.secure_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.secure_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_secure_redirects

    - name: Comment out any occurrences of net.ipv4.conf.default.secure_redirects from
        config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.secure_redirects
        replace: '#net.ipv4.conf.default.secure_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_secure_redirects
    - name: XCCDF Value sysctl_net_ipv4_conf_default_secure_redirects_value # promote to variable
      set_fact:
        sysctl_net_ipv4_conf_default_secure_redirects_value: !!str 0
      tags:
        - always

    - name: Ensure sysctl net.ipv4.conf.default.secure_redirects is set
      sysctl:
        name: net.ipv4.conf.default.secure_redirects
        value: '{{ sysctl_net_ipv4_conf_default_secure_redirects_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_secure_redirects

#### Rule Enable Kernel Parameter to Ignore ICMP Broadcast Echo Requests on IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.icmp_echo_ignore_broadcasts` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.icmp_echo_ignore_broadcasts=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.icmp_echo_ignore_broadcasts = 1

Rationale: | Responding to broadcast (ICMP) echoes facilitates network mapping and provides a vector for amplification attacks. Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_echo_ignore_broadcasts

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227, OL07-00-040630, SV-221877r880648_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.icmp_echo_ignore_broadcasts" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value='1'

    #
    # Set runtime for net.ipv4.icmp_echo_ignore_broadcasts
    #
    /sbin/sysctl -q -n -w net.ipv4.icmp_echo_ignore_broadcasts="$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"

    #
    # If net.ipv4.icmp_echo_ignore_broadcasts present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.icmp_echo_ignore_broadcasts = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_echo_ignore_broadcasts")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_echo_ignore_broadcasts\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_echo_ignore_broadcasts\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040630
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_icmp_echo_ignore_broadcasts

    - name: Comment out any occurrences of net.ipv4.icmp_echo_ignore_broadcasts from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.icmp_echo_ignore_broadcasts
        replace: '#net.ipv4.icmp_echo_ignore_broadcasts'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040630
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_icmp_echo_ignore_broadcasts
    - name: XCCDF Value sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value # promote to variable
      set_fact:
        sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.icmp_echo_ignore_broadcasts is set
      sysctl:
        name: net.ipv4.icmp_echo_ignore_broadcasts
        value: '{{ sysctl_net_ipv4_icmp_echo_ignore_broadcasts_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040630
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_icmp_echo_ignore_broadcasts

#### Rule Enable Kernel Parameter to Ignore Bogus ICMP Error Responses on IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.icmp_ignore_bogus_error_responses` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.icmp_ignore_bogus_error_responses=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.icmp_ignore_bogus_error_responses = 1

Rationale: | Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_icmp_ignore_bogus_error_responses

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, Req-1.4.3, 1.4.2, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.icmp_ignore_bogus_error_responses" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value='1'

    #
    # Set runtime for net.ipv4.icmp_ignore_bogus_error_responses
    #
    /sbin/sysctl -q -n -w net.ipv4.icmp_ignore_bogus_error_responses="$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"

    #
    # If net.ipv4.icmp_ignore_bogus_error_responses present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.icmp_ignore_bogus_error_responses = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.icmp_ignore_bogus_error_responses")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.icmp_ignore_bogus_error_responses\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.icmp_ignore_bogus_error_responses\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
      - unknown_severity

    - name: Comment out any occurrences of net.ipv4.icmp_ignore_bogus_error_responses
        from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.icmp_ignore_bogus_error_responses
        replace: '#net.ipv4.icmp_ignore_bogus_error_responses'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
      - unknown_severity
    - name: XCCDF Value sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value # promote to variable
      set_fact:
        sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.icmp_ignore_bogus_error_responses is set
      sysctl:
        name: net.ipv4.icmp_ignore_bogus_error_responses
        value: '{{ sysctl_net_ipv4_icmp_ignore_bogus_error_responses_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - PCI-DSS-Req-1.4.3
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - low_complexity
      - medium_disruption
      - reboot_required
      - sysctl_net_ipv4_icmp_ignore_bogus_error_responses
      - unknown_severity

#### Rule Enable Kernel Parameter to Use TCP Syncookies on Network Interfaces [ref]

To set the runtime status of the `net.ipv4.tcp_syncookies` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.tcp_syncookies=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.tcp_syncookies = 1

Rationale:

A TCP SYN flood attack can cause a denial of service by filling a system's TCP connection table with connections in the SYN_RCVD state. Syncookies can be used to track a connection when a subsequent ACK is received, verifying the initiator is attempting a valid connection and is not a flood source. This feature is activated when a flood condition is detected, and enables the system to continue servicing valid connection requests.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_tcp_syncookies

Identifiers and References

References: BP28(R22), 1, 12, 13, 14, 15, 16, 18, 2, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.07, DSS06.02, 3.1.20, CCI-000366, CCI-001095, 4.2.3.4, 4.3.3.4, 4.4.3.3, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), SC-5(1), SC-5(2), SC-5(3)(a), CM-6(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.PT-4, Req-1.4.1, 1.4.3, SRG-OS-000480-GPOS-00227, SRG-OS-000420-GPOS-00186, SRG-OS-000142-GPOS-00071

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.tcp_syncookies from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.tcp_syncookies.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.tcp_syncookies" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_net_ipv4_tcp_syncookies_value='1'

    #
    # Set runtime for net.ipv4.tcp_syncookies
    #
    /sbin/sysctl -q -n -w net.ipv4.tcp_syncookies="$sysctl_net_ipv4_tcp_syncookies_value"

    #
    # If net.ipv4.tcp_syncookies present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "net.ipv4.tcp_syncookies = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.tcp_syncookies")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_net_ipv4_tcp_syncookies_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.tcp_syncookies\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.tcp_syncookies\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.tcp_syncookies.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(1)
      - NIST-800-53-SC-5(2)
      - NIST-800-53-SC-5(3)(a)
      - PCI-DSS-Req-1.4.1
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_tcp_syncookies

    - name: Comment out any occurrences of net.ipv4.tcp_syncookies from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.tcp_syncookies
        replace: '#net.ipv4.tcp_syncookies'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(1)
      - NIST-800-53-SC-5(2)
      - NIST-800-53-SC-5(3)(a)
      - PCI-DSS-Req-1.4.1
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_tcp_syncookies
    - name: XCCDF Value sysctl_net_ipv4_tcp_syncookies_value # promote to variable
      set_fact:
        sysctl_net_ipv4_tcp_syncookies_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl net.ipv4.tcp_syncookies is set
      sysctl:
        name: net.ipv4.tcp_syncookies
        value: '{{ sysctl_net_ipv4_tcp_syncookies_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5(1)
      - NIST-800-53-SC-5(2)
      - NIST-800-53-SC-5(3)(a)
      - PCI-DSS-Req-1.4.1
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_tcp_syncookies

Group Network Parameters for Hosts Only Group contains 3 rules
[ref] If the system is not going to be used as a router, then setting certain kernel parameters ensure that the host will not perform routing of network traffic.

#### Rule Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.conf.all.send_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.all.send_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.all.send_redirects = 0

Rationale: | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_all_send_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 1.4.5, SRG-OS-000480-GPOS-00227, OL07-00-040660, SV-221881r880660_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.all.send_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.all.send_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.all.send_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for net.ipv4.conf.all.send_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.all.send_redirects="0"

    #
    # If net.ipv4.conf.all.send_redirects present in /etc/sysctl.conf, change value to "0"
    #	else, add "net.ipv4.conf.all.send_redirects = 0" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.all.send_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "0"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.all.send_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.all.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.all.send_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040660
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_send_redirects

    - name: Comment out any occurrences of net.ipv4.conf.all.send_redirects from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.all.send_redirects
        replace: '#net.ipv4.conf.all.send_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040660
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_send_redirects

    - name: Ensure sysctl net.ipv4.conf.all.send_redirects is set to 0
      sysctl:
        name: net.ipv4.conf.all.send_redirects
        value: '0'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040660
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_all_send_redirects

#### Rule Disable Kernel Parameter for Sending ICMP Redirects on all IPv4 Interfaces by Default [ref]

To set the runtime status of the `net.ipv4.conf.default.send_redirects` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.conf.default.send_redirects=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.conf.default.send_redirects = 0

Rationale: | ICMP redirect messages are used by routers to inform hosts that a more direct route exists for a particular destination. These messages contain information from the system's route table possibly revealing portions of the network topology. The ability to send ICMP redirects is only appropriate for systems acting as routers.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_conf_default_send_redirects

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 4, 6, 7, 8, 9, 5.10.1.1, APO01.06, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS01.05, DSS03.01, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, 3.1.20, CCI-000366, 4.2.3.4, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.AE-1, DE.CM-1, ID.AM-3, PR.AC-5, PR.DS-4, PR.DS-5, PR.IP-1, PR.PT-3, PR.PT-4, 1.4.5, SRG-OS-000480-GPOS-00227, OL07-00-040650, SV-221880r880657_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.conf.default.send_redirects from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.conf.default.send_redirects.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.conf.default.send_redirects" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for net.ipv4.conf.default.send_redirects
    #
    /sbin/sysctl -q -n -w net.ipv4.conf.default.send_redirects="0"

    #
    # If net.ipv4.conf.default.send_redirects present in /etc/sysctl.conf, change value to "0"
    #	else, add "net.ipv4.conf.default.send_redirects = 0" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.conf.default.send_redirects")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "0"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.conf.default.send_redirects\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.conf.default.send_redirects\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.conf.default.send_redirects.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040650
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_send_redirects

    - name: Comment out any occurrences of net.ipv4.conf.default.send_redirects from config
        files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.conf.default.send_redirects
        replace: '#net.ipv4.conf.default.send_redirects'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040650
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_send_redirects

    - name: Ensure sysctl net.ipv4.conf.default.send_redirects is set to 0
      sysctl:
        name: net.ipv4.conf.default.send_redirects
        value: '0'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1.1
      - DISA-STIG-OL07-00-040650
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSSv4-1.4.5
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_conf_default_send_redirects

#### Rule Disable Kernel Parameter for IP Forwarding on IPv4 Interfaces [ref]

To set the runtime status of the `net.ipv4.ip_forward` kernel parameter, run the following command:

    $ sudo sysctl -w net.ipv4.ip_forward=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    net.ipv4.ip_forward = 0

Warning: Certain technologies such as virtual machines, containers, etc. rely on IPv4 forwarding to enable and use networking. Disabling IPv4 forwarding would cause those technologies to stop working. Therefore, this rule should not be used in profiles or benchmarks that target usage of IPv4 forwarding.

Rationale: | Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If this capability is used when not required, system network information may be unnecessarily transmitted across the network.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_net_ipv4_ip_forward

Identifiers and References

References: BP28(R22), 1, 11, 12, 13, 14, 15, 16, 2, 3, 7, 8, 9, APO13.01, BAI04.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.05, DSS05.07, DSS06.06, 3.1.20, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 6.2, SR 7.1, SR 7.2, SR 7.6, A.12.1.2, A.12.1.3, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.17.2.1, A.9.1.2, CIP-007-3 R4, CIP-007-3 R4.1, CIP-007-3 R4.2, CIP-007-3 R5.1, CM-7(a), CM-7(b), SC-5, CM-6(a), SC-7(a), DE.CM-1, PR.DS-4, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.3.1, Req-1.3.2, 1.4.3, SRG-OS-000480-GPOS-00227, OL07-00-040740, SV-221889r880663_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of net.ipv4.ip_forward from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*net.ipv4.ip_forward.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "net.ipv4.ip_forward" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for net.ipv4.ip_forward
    #
    /sbin/sysctl -q -n -w net.ipv4.ip_forward="0"

    #
    # If net.ipv4.ip_forward present in /etc/sysctl.conf, change value to "0"
    #	else, add "net.ipv4.ip_forward = 0" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^net.ipv4.ip_forward")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "0"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^net.ipv4.ip_forward\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^net.ipv4.ip_forward\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*net.ipv4.ip_forward.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040740
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.3.1
      - PCI-DSS-Req-1.3.2
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_ip_forward

    - name: Comment out any occurrences of net.ipv4.ip_forward from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*net.ipv4.ip_forward
        replace: '#net.ipv4.ip_forward'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040740
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.3.1
      - PCI-DSS-Req-1.3.2
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_ip_forward

    - name: Ensure sysctl net.ipv4.ip_forward is set to 0
      sysctl:
        name: net.ipv4.ip_forward
        value: '0'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040740
      - NIST-800-171-3.1.20
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-SC-5
      - NIST-800-53-SC-7(a)
      - PCI-DSS-Req-1.3.1
      - PCI-DSS-Req-1.3.2
      - PCI-DSSv4-1.4.3
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_net_ipv4_ip_forward

Group Uncommon Network Protocols Group contains 2 rules

[ref] The system includes support for several network protocols which are not commonly used. Although security vulnerabilities in kernel networking code are not frequently discovered, the consequences can be dramatic. Ensuring uncommon network protocols are disabled reduces the system's risk to attacks targeted at its implementation of those protocols.
Warning: Although these protocols are not commonly used, avoid disruption in your network environment by ensuring they are not needed prior to disabling them.

#### Rule Disable DCCP Support [ref]

The Datagram Congestion Control Protocol (DCCP) is a relatively new transport layer protocol, designed to support streaming media and telephony. To configure the system to prevent the `dccp` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/dccp.conf`:

    install dccp /bin/true

To configure the system to prevent the `dccp` from being used, add the following line to file `/etc/modprobe.d/dccp.conf`:

    blacklist dccp

Rationale: | Disabling DCCP protects the system against exploitation of any flaws in its implementation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_dccp_disabled

Identifiers and References

References: 11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-001958, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, Req-1.4.2, 1.4.2, SRG-OS-000096-GPOS-00050, SRG-OS-000378-GPOS-00163, OL07-00-020101, SV-221713r853673_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install dccp" /etc/modprobe.d/dccp.conf ; then

    	sed -i 's#^install dccp.*#install dccp /bin/true#g' /etc/modprobe.d/dccp.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/dccp.conf
    	echo "install dccp /bin/true" >> /etc/modprobe.d/dccp.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist dccp$" /etc/modprobe.d/dccp.conf ; then
    	echo "blacklist dccp" >> /etc/modprobe.d/dccp.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'dccp' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/dccp.conf
        regexp: install\s+dccp
        line: install dccp /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1
      - DISA-STIG-OL07-00-020101
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.2
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - kernel_module_dccp_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

    - name: Ensure kernel module 'dccp' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/dccp.conf
        regexp: ^blacklist dccp$
        line: blacklist dccp
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1
      - DISA-STIG-OL07-00-020101
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.2
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - kernel_module_dccp_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

#### Rule Disable SCTP Support [ref]

The Stream Control Transmission Protocol (SCTP) is a transport layer protocol, designed to support the idea of message-oriented communication, with several streams of messages within one connection. To configure the system to prevent the `sctp` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/sctp.conf`:

    install sctp /bin/true

To configure the system to prevent the `sctp` from being used, add the following line to file `/etc/modprobe.d/sctp.conf`:

    blacklist sctp

Rationale: | Disabling SCTP protects the system against exploitation of any flaws in its implementation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_sctp_disabled

Identifiers and References

References: 11, 14, 3, 9, 5.10.1, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-000381, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, Req-1.4.2, 1.4.2, SRG-OS-000095-GPOS-00049, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install sctp" /etc/modprobe.d/sctp.conf ; then

    	sed -i 's#^install sctp.*#install sctp /bin/true#g' /etc/modprobe.d/sctp.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/sctp.conf
    	echo "install sctp /bin/true" >> /etc/modprobe.d/sctp.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist sctp$" /etc/modprobe.d/sctp.conf ; then
    	echo "blacklist sctp" >> /etc/modprobe.d/sctp.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'sctp' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/sctp.conf
        regexp: install\s+sctp
        line: install sctp /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.2
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - kernel_module_sctp_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

    - name: Ensure kernel module 'sctp' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/sctp.conf
        regexp: ^blacklist sctp$
        line: blacklist sctp
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.10.1
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-1.4.2
      - PCI-DSSv4-1.4.2
      - disable_strategy
      - kernel_module_sctp_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

Group Wireless Networking Group contains 1 group and 3 rules

[ref] Wireless networking, such as 802.11 (WiFi) and Bluetooth, can present a security risk to sensitive or classified systems and networks. Wireless networking hardware is much more likely to be included in laptop or portable systems than in desktops or servers.
Removal of hardware provides the greatest assurance that the wireless capability remains disabled. Acquisition policies often include provisions to prevent the purchase of equipment that will be used in sensitive spaces and includes wireless capabilities. If it is impractical to remove the wireless hardware, and policy permits the device to enter sensitive spaces as long as wireless is disabled, efforts should instead focus on disabling wireless capability via software.

Group Disable Wireless Through Software Configuration Group contains 3 rules
[ref] If it is impossible to remove the wireless hardware from the device in question, disable as much of it as possible through software. The following methods can disable software support for wireless networking, but note that these methods do not prevent malicious software or careless users from re-activating the devices.

#### Rule Disable Bluetooth Service [ref]

The `bluetooth` service can be disabled with the following command:

    $ sudo systemctl mask --now bluetooth.service

    $ sudo service bluetooth stop

Rationale: | Disabling the `bluetooth` service prevents the system from attempting connections to Bluetooth devices, which entails some security risk. Nevertheless, variation in this risk decision may be expected due to the utility of Bluetooth connectivity and its limited range.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_bluetooth_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-001551, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'bluetooth.service'
    "$SYSTEMCTL_EXEC" disable 'bluetooth.service'
    "$SYSTEMCTL_EXEC" mask 'bluetooth.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files bluetooth.socket; then
        "$SYSTEMCTL_EXEC" stop 'bluetooth.socket'
        "$SYSTEMCTL_EXEC" mask 'bluetooth.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'bluetooth.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service bluetooth
      block:

      - name: Disable service bluetooth
        block:

        - name: Disable service bluetooth
          systemd:
            name: bluetooth.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service bluetooth' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_bluetooth_disabled

    - name: Unit Socket Exists - bluetooth.socket
      command: systemctl -q list-unit-files bluetooth.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_bluetooth_disabled

    - name: Disable socket bluetooth
      systemd:
        name: bluetooth.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("bluetooth.socket",multiline=True)
      tags:
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_bluetooth_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["bluetooth"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_bluetooth

    class disable_bluetooth {
      service {'bluetooth':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Disable Bluetooth Kernel Module [ref]

The kernel's module loading system can be configured to prevent loading of the Bluetooth module. Add the following to the appropriate `/etc/modprobe.d` configuration file to prevent the loading of the Bluetooth module:

    install bluetooth /bin/true

Rationale: | If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_bluetooth_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, 5.13.1.3, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-001443, CCI-001444, CCI-001551, CCI-002418, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000095-GPOS-00049, SRG-OS-000300-GPOS-00118

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install bluetooth" /etc/modprobe.d/bluetooth.conf ; then

    	sed -i 's#^install bluetooth.*#install bluetooth /bin/true#g' /etc/modprobe.d/bluetooth.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/bluetooth.conf
    	echo "install bluetooth /bin/true" >> /etc/modprobe.d/bluetooth.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist bluetooth$" /etc/modprobe.d/bluetooth.conf ; then
    	echo "blacklist bluetooth" >> /etc/modprobe.d/bluetooth.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'bluetooth' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/bluetooth.conf
        regexp: install\s+bluetooth
        line: install bluetooth /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.13.1.3
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - kernel_module_bluetooth_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

    - name: Ensure kernel module 'bluetooth' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/bluetooth.conf
        regexp: ^blacklist bluetooth$
        line: blacklist bluetooth
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.13.1.3
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - kernel_module_bluetooth_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

#### Rule Deactivate Wireless Network Interfaces [ref]

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.
Configure the system to disable all wireless network interfaces with the following command:

    $ sudo nmcli radio all off

Rationale:

The use of wireless networking can introduce many different attack vectors into the organization's network. Common attack vectors such as malicious association and ad hoc networks will allow an attacker to spoof a wireless access point (AP), allowing validated systems to connect to the malicious AP and enabling the attacker to monitor and record network traffic. These malicious APs can also serve to create a man-in-the-middle attack or be used to create a denial of service to valid network resources.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_wireless_disable_interfaces

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.16, CCI-000085, CCI-002418, CCI-002421, CCI-001443, CCI-001444, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 1315, 1319, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-18(a), AC-18(3), CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-1.3.3, 1.3.3, 2.3, SRG-OS-000299-GPOS-00117, SRG-OS-000300-GPOS-00118, SRG-OS-000424-GPOS-00188, SRG-OS-000481-GPOS-000481, OL07-00-041010, SV-221898r877465_rule

Remediation Shell script ⇲

    if ! rpm -q --quiet "NetworkManager" ; then
        yum install -y "NetworkManager"
    fi

    nmcli radio all off

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - DISA-STIG-OL07-00-041010
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - PCI-DSS-Req-1.3.3
      - PCI-DSSv4-1.3.3
      - PCI-DSSv4-2.3
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
      - wireless_disable_interfaces

    - name: Ensure NetworkManager is installed
      ansible.builtin.package:
        name: '{{ item }}'
        state: present
      with_items:
      - NetworkManager
      tags:
      - DISA-STIG-OL07-00-041010
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - PCI-DSS-Req-1.3.3
      - PCI-DSSv4-1.3.3
      - PCI-DSSv4-2.3
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
      - wireless_disable_interfaces

    - name: Deactivate Wireless Network Interfaces
      command: nmcli radio wifi off
      when: '''NetworkManager'' in ansible_facts.packages'
      tags:
      - DISA-STIG-OL07-00-041010
      - NIST-800-171-3.1.16
      - NIST-800-53-AC-18(3)
      - NIST-800-53-AC-18(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - PCI-DSS-Req-1.3.3
      - PCI-DSSv4-1.3.3
      - PCI-DSSv4-2.3
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - unknown_strategy
      - wireless_disable_interfaces

#### Rule Ensure System is Not Acting as a Network Sniffer [ref]

The system should not be acting as a network sniffer, which can capture all traffic on the network to which it is connected. Run the following to determine if any interface is running in promiscuous mode:

    $ ip link | grep PROMISC

Promiscuous mode of an interface can be disabled with the following command:

    $ sudo ip link set dev device_name multicast off promisc off

Rationale:

Network interfaces in promiscuous mode allow for the capture of all network traffic visible to the system. If unauthorized individuals can access these applications, it may allow them to collect information such as logon IDs, passwords, and key exchanges between systems.
If the system is being used to perform a network troubleshooting function, the use of these tools must be documented with the Information Systems Security Manager (ISSM) and restricted to only authorized personnel.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_network_sniffer_disabled

Identifiers and References

References: 1, 11, 14, 3, 9, APO11.06, APO12.06, BAI03.10, BAI09.01, BAI09.02, BAI09.03, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.05, DSS04.05, DSS05.02, DSS05.05, DSS06.06, CCI-000366, 4.2.3.4, 4.3.3.3.7, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, SR 7.8, A.11.1.2, A.11.2.4, A.11.2.5, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.16.1.6, A.8.1.1, A.8.1.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), CM-7(2), MA-3, DE.DP-5, ID.AM-1, PR.IP-1, PR.MA-1, PR.PT-3, 1.4.5, SRG-OS-000480-GPOS-00227, OL07-00-040670, SV-221882r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    for interface in $(ip link show | grep -E '^[0-9]' | cut -d ":" -f 2); do
        ip link set dev $interface multicast off promisc off
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Ensure System is Not Acting as a Network Sniffer - Gather network interfaces
      ansible.builtin.command:
        cmd: ip link show
      register: network_interfaces
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040670
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(2)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MA-3
      - PCI-DSSv4-1.4.5
      - low_complexity
      - low_disruption
      - medium_severity
      - network_sniffer_disabled
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure System is Not Acting as a Network Sniffer - Disable promiscuous mode
      ansible.builtin.command:
        cmd: ip link set dev {{ item.split(':')[1] }} multicast off promisc off
      loop: '{{ network_interfaces.stdout_lines }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - item.split(':') | length == 3
      tags:
      - DISA-STIG-OL07-00-040670
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(2)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MA-3
      - PCI-DSSv4-1.4.5
      - low_complexity
      - low_disruption
      - medium_severity
      - network_sniffer_disabled
      - no_reboot_needed
      - restrict_strategy

Group File Permissions and Masks Group contains 7 groups and 34 rules

[ref] Traditional Unix security relies heavily on file and directory permissions to prevent unauthorized users from reading or modifying files to which they should not have access.
Several of the commands in this section search filesystems for files or directories with certain characteristics, and are intended to be run on every local partition on a given system. When the variable PART appears in one of the commands below, it means that the command is intended to be run repeatedly, with the name of each local partition substituted for PART in turn.
The following command prints a list of all xfs partitions on the local system, which is the default filesystem for Oracle Linux 7 installations:

    $ mount -t xfs | awk '{print $3}'

For any systems that use a different local filesystem type, modify this command as appropriate.

Group Verify Permissions on Important Files and Directories Group contains 5 rules
[ref] Permissions for many files on a system must be set restrictively to ensure sensitive information is properly protected. This section discusses important permission restrictions which can be verified to ensure that no harmful discrepancies have arisen.

#### Rule Ensure All World-Writable Directories Are Owned by a System Account [ref]

All directories in local partitions which are world-writable should be owned by root or another system account. If any world-writable directories are not owned by a system account, this should be investigated. Following this, the files should be deleted or assigned to an appropriate owner.
Rationale: | Allowing a user account to own a world-writable directory is undesirable because it allows the owner of that directory to remove or replace any files that may be placed in the directory by other users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_dir_perms_world_writable_system_owned

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-021031, SV-228566r744092_rule

#### Rule Ensure All Files Are Owned by a Group [ref]

If any files are not owned by a group, then the cause of their lack of group-ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate group. The following command will discover and print any files on local partitions which do not belong to a valid group:

    $ df --local -P | awk '{if (NR!=1) print $6}' | sudo xargs -I '{}' find '{}' -xdev -nogroup

To search all filesystems on a system including network mounted filesystems the following command can be run manually for each partition:

    $ sudo find PARTITION -xdev -nogroup

Warning: This rule only considers local groups. If you have your groups defined outside `/etc/group`, the rule won't consider those.

Rationale:

Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_ungroupowned

Identifiers and References

References: BP28(R55), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-020330, SV-221725r603260_rule

#### Rule Ensure All Files Are Owned by a User [ref]

If any files are not owned by a user, then the cause of their lack of ownership should be investigated. Following this, the files should be deleted or assigned to an appropriate user. The following command will discover and print any files on local partitions which do not belong to a valid user:

    $ df --local -P | awk {'if (NR!=1) print $6'} | sudo xargs -I '{}' find '{}' -xdev -nouser

To search all filesystems on a system including network mounted filesystems the following command can be run manually for each partition:

    $ sudo find PARTITION -xdev -nouser

Warning: For this rule to evaluate centralized user accounts, `getent` must be working properly so that running the command

    getent passwd

returns a list of all users in your organization. If using the System Security Services Daemon (SSSD),

    enumerate = true

must be configured in your organization's domain to return a complete list of users
Warning: Enabling this rule will result in slower scan times depending on the size of your organization and number of centralized users.

Rationale:

Unowned files do not directly imply a security problem, but they are generally a sign that something is amiss. They may be caused by an intruder, by incorrect software installation or draft software removal, or by failure to remove all files belonging to a deleted account. The files should be repaired so they will not cause problems when accounts are created in the future, and the cause should be discovered and addressed.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_no_files_unowned_by_user

Identifiers and References

References: BP28(R55), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, CCI-002165, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-020320, SV-221724r603260_rule

#### Rule Enable Kernel Parameter to Enforce DAC on Hardlinks [ref]

To set the runtime status of the `fs.protected_hardlinks` kernel parameter, run the following command:

    $ sudo sysctl -w fs.protected_hardlinks=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    fs.protected_hardlinks = 1

Rationale: | By enabling this kernel parameter, users can no longer create soft or hard links to files which they do not own. Disallowing such hardlinks mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of `open()` or `creat()`.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_protected_hardlinks
Identifiers and References | References: BP28(R23), CCI-002165, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of fs.protected_hardlinks from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*fs.protected_hardlinks.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "fs.protected_hardlinks" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for fs.protected_hardlinks
    #
    /sbin/sysctl -q -n -w fs.protected_hardlinks="1"

    #
    # If fs.protected_hardlinks present in /etc/sysctl.conf, change value to "1"
    #	else, add "fs.protected_hardlinks = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.protected_hardlinks")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^fs.protected_hardlinks\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^fs.protected_hardlinks\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*fs.protected_hardlinks.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_hardlinks

    - name: Comment out any occurrences of fs.protected_hardlinks from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*fs.protected_hardlinks
        replace: '#fs.protected_hardlinks'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_hardlinks

    - name: Ensure sysctl fs.protected_hardlinks is set to 1
      sysctl:
        name: fs.protected_hardlinks
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_hardlinks

#### Rule Enable Kernel Parameter to Enforce DAC on Symlinks [ref]

To set the runtime status of the `fs.protected_symlinks` kernel parameter, run the following command:

    $ sudo sysctl -w fs.protected_symlinks=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    fs.protected_symlinks = 1

Rationale:

By enabling this kernel parameter, symbolic links are permitted to be followed only when outside a sticky world-writable directory, or when the UID of the link and follower match, or when the directory owner matches the symlink's owner. Disallowing such symlinks helps mitigate vulnerabilities based on insecure file system accessed by privileged programs, avoiding an exploitation vector exploiting unsafe use of `open()` or `creat()`.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_protected_symlinks
Identifiers and References | References: BP28(R23), CCI-002165, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-6(1), SRG-OS-000312-GPOS-00122, SRG-OS-000312-GPOS-00123, SRG-OS-000324-GPOS-00125

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of fs.protected_symlinks from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*fs.protected_symlinks.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "fs.protected_symlinks" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for fs.protected_symlinks
    #
    /sbin/sysctl -q -n -w fs.protected_symlinks="1"

    #
    # If fs.protected_symlinks present in /etc/sysctl.conf, change value to "1"
    #	else, add "fs.protected_symlinks = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.protected_symlinks")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^fs.protected_symlinks\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^fs.protected_symlinks\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*fs.protected_symlinks.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_symlinks

    - name: Comment out any occurrences of fs.protected_symlinks from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*fs.protected_symlinks
        replace: '#fs.protected_symlinks'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_symlinks

    - name: Ensure sysctl fs.protected_symlinks is set to 1
      sysctl:
        name: fs.protected_symlinks
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_protected_symlinks

Group Restrict Dynamic Mounting and Unmounting of Filesystems Group contains 6 rules

[ref] Linux includes a number of facilities for the automated addition and removal of filesystems on a running system. These facilities may be necessary in many environments, but this capability also carries some risk -- whether direct risk from allowing users to introduce arbitrary filesystems, or risk that software flaws in the automated mount facility itself could allow an attacker to compromise the system.
This command can be used to list the types of filesystems that are available to the currently executing kernel:

    $ find /lib/modules/`uname -r`/kernel/fs -type f -name '*.ko'

If these filesystems are not required then they can be explicitly disabled in a configuratio file in `/etc/modprobe.d`.

#### Rule Disable the Automounter [ref]

The `autofs` daemon mounts and unmounts filesystems, such as user home directories shared via NFS, on demand. In addition, autofs can be used to handle removable media, and the default configuration provides the cdrom device as `/misc/cd`. However, this method of providing access to removable media is not common, so autofs can almost always be disabled if NFS is not in use. Even if NFS is required, it may be possible to configure filesystem mounts statically by editing `/etc/fstab` rather than relying on the automounter.
The `autofs` service can be disabled with the following command:

    $ sudo systemctl mask --now autofs.service

Rationale: | Disabling the automounter permits the administrator to statically control filesystem mounting through `/etc/fstab`. Additionally, automatically mounting filesystems permits easy introduction of unknown devices, thereby facilitating malicious activity.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_autofs_disabled

Identifiers and References

References: 1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.4.6, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, OL07-00-020110, SV-221714r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'autofs.service'
    "$SYSTEMCTL_EXEC" disable 'autofs.service'
    "$SYSTEMCTL_EXEC" mask 'autofs.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files autofs.socket; then
        "$SYSTEMCTL_EXEC" stop 'autofs.socket'
        "$SYSTEMCTL_EXEC" mask 'autofs.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'autofs.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service autofs
      block:

      - name: Disable service autofs
        block:

        - name: Disable service autofs
          systemd:
            name: autofs.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service autofs' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020110
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_autofs_disabled

    - name: Unit Socket Exists - autofs.socket
      command: systemctl -q list-unit-files autofs.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020110
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_autofs_disabled

    - name: Disable socket autofs
      systemd:
        name: autofs.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("autofs.socket",multiline=True)
      tags:
      - DISA-STIG-OL07-00-020110
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_autofs_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["autofs"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_autofs

    class disable_autofs {
      service {'autofs':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Disable Mounting of cramfs [ref]

To configure the system to prevent the `cramfs` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/cramfs.conf`:

    install cramfs /bin/true

To configure the system to prevent the `cramfs` from being used, add the following line to file `/etc/modprobe.d/cramfs.conf`:

    blacklist cramfs

This effectively prevents usage of this uncommon filesystem. The `cramfs` filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems. A `cramfs` image can be used without having to first decompress the image.

Rationale: | Removing support for unneeded filesystem types reduces the local attack surface of the server.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_cramfs_disabled

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, CCI-000381, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3, SRG-OS-000095-GPOS-00049

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install cramfs" /etc/modprobe.d/cramfs.conf ; then

    	sed -i 's#^install cramfs.*#install cramfs /bin/true#g' /etc/modprobe.d/cramfs.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/cramfs.conf
    	echo "install cramfs /bin/true" >> /etc/modprobe.d/cramfs.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist cramfs$" /etc/modprobe.d/cramfs.conf ; then
    	echo "blacklist cramfs" >> /etc/modprobe.d/cramfs.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'cramfs' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/cramfs.conf
        regexp: install\s+cramfs
        line: install cramfs /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_cramfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

    - name: Ensure kernel module 'cramfs' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/cramfs.conf
        regexp: ^blacklist cramfs$
        line: blacklist cramfs
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_cramfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

#### Rule Disable Mounting of freevxfs [ref]

To configure the system to prevent the `freevxfs` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/freevxfs.conf`:

    install freevxfs /bin/true

To configure the system to prevent the `freevxfs` from being used, add the following line to file `/etc/modprobe.d/freevxfs.conf`:

    blacklist freevxfs

This effectively prevents usage of this uncommon filesystem.

Rationale: | Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_freevxfs_disabled

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install freevxfs" /etc/modprobe.d/freevxfs.conf ; then

    	sed -i 's#^install freevxfs.*#install freevxfs /bin/true#g' /etc/modprobe.d/freevxfs.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/freevxfs.conf
    	echo "install freevxfs /bin/true" >> /etc/modprobe.d/freevxfs.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist freevxfs$" /etc/modprobe.d/freevxfs.conf ; then
    	echo "blacklist freevxfs" >> /etc/modprobe.d/freevxfs.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'freevxfs' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/freevxfs.conf
        regexp: install\s+freevxfs
        line: install freevxfs /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_freevxfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

    - name: Ensure kernel module 'freevxfs' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/freevxfs.conf
        regexp: ^blacklist freevxfs$
        line: blacklist freevxfs
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_freevxfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

#### Rule Disable Mounting of jffs2 [ref]

To configure the system to prevent the `jffs2` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/jffs2.conf`:

    install jffs2 /bin/true

To configure the system to prevent the `jffs2` from being used, add the following line to file `/etc/modprobe.d/jffs2.conf`:

    blacklist jffs2

This effectively prevents usage of this uncommon filesystem.

Rationale: | Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_jffs2_disabled

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install jffs2" /etc/modprobe.d/jffs2.conf ; then

    	sed -i 's#^install jffs2.*#install jffs2 /bin/true#g' /etc/modprobe.d/jffs2.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/jffs2.conf
    	echo "install jffs2 /bin/true" >> /etc/modprobe.d/jffs2.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist jffs2$" /etc/modprobe.d/jffs2.conf ; then
    	echo "blacklist jffs2" >> /etc/modprobe.d/jffs2.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'jffs2' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/jffs2.conf
        regexp: install\s+jffs2
        line: install jffs2 /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_jffs2_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

    - name: Ensure kernel module 'jffs2' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/jffs2.conf
        regexp: ^blacklist jffs2$
        line: blacklist jffs2
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_jffs2_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

#### Rule Disable Mounting of squashfs [ref]

To configure the system to prevent the `squashfs` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/squashfs.conf`:

    install squashfs /bin/true

To configure the system to prevent the `squashfs` from being used, add the following line to file `/etc/modprobe.d/squashfs.conf`:

    blacklist squashfs

This effectively prevents usage of this uncommon filesystem. The `squashfs` filesystem type is a compressed read-only Linux filesystem embedded in small footprint systems (similar to `cramfs`). A `squashfs` image can be used without having to first decompress the image.

Rationale: | Removing support for unneeded filesystem types reduces the local attack surface of the system.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_squashfs_disabled

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 3.4.6, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install squashfs" /etc/modprobe.d/squashfs.conf ; then

    	sed -i 's#^install squashfs.*#install squashfs /bin/true#g' /etc/modprobe.d/squashfs.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/squashfs.conf
    	echo "install squashfs /bin/true" >> /etc/modprobe.d/squashfs.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist squashfs$" /etc/modprobe.d/squashfs.conf ; then
    	echo "blacklist squashfs" >> /etc/modprobe.d/squashfs.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'squashfs' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/squashfs.conf
        regexp: install\s+squashfs
        line: install squashfs /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_squashfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

    - name: Ensure kernel module 'squashfs' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/squashfs.conf
        regexp: ^blacklist squashfs$
        line: blacklist squashfs
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.6
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - kernel_module_squashfs_disabled
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required

#### Rule Disable Modprobe Loading of USB Storage Driver [ref]

To prevent USB storage devices from being used, configure the kernel module loading system to prevent automatic loading of the USB storage driver. To configure the system to prevent the `usb-storage` kernel module from being loaded, add the following line to the file `/etc/modprobe.d/usb-storage.conf`:

    install usb-storage /bin/true

To configure the system to prevent the `usb-storage` from being used, add the following line to file `/etc/modprobe.d/usb-storage.conf`:

    blacklist usb-storage

This will prevent the `modprobe` program from loading the `usb-storage` module, but will not prevent an administrator (or another program) from using the `insmod` program to load the module manually.

Rationale: | USB storage devices such as thumb drives can be used to introduce malicious software.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_kernel_module_usb-storage_disabled

Identifiers and References

References: 1, 12, 15, 16, 5, APO13.01, DSS01.04, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.21, CCI-000366, CCI-000778, CCI-001958, 164.308(a)(3)(i), 164.308(a)(3)(ii)(A), 164.310(d)(1), 164.310(d)(2), 164.312(a)(1), 164.312(a)(2)(iv), 164.312(b), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, A.11.2.6, A.13.1.1, A.13.2.1, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), MP-7, PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, 3.4.2, SRG-OS-000114-GPOS-00059, SRG-OS-000378-GPOS-00163, SRG-OS-000480-GPOS-00227, OL07-00-020100, SV-221712r853672_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if LC_ALL=C grep -q -m 1 "^install usb-storage" /etc/modprobe.d/usb-storage.conf ; then

    	sed -i 's#^install usb-storage.*#install usb-storage /bin/true#g' /etc/modprobe.d/usb-storage.conf
    else
    	echo -e "\n# Disable per security requirements" >> /etc/modprobe.d/usb-storage.conf
    	echo "install usb-storage /bin/true" >> /etc/modprobe.d/usb-storage.conf
    fi

    if ! LC_ALL=C grep -q -m 1 "^blacklist usb-storage$" /etc/modprobe.d/usb-storage.conf ; then
    	echo "blacklist usb-storage" >> /etc/modprobe.d/usb-storage.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: Ensure kernel module 'usb-storage' is disabled
      lineinfile:
        create: true
        dest: /etc/modprobe.d/usb-storage.conf
        regexp: install\s+usb-storage
        line: install usb-storage /bin/true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020100
      - NIST-800-171-3.1.21
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - PCI-DSSv4-3.4.2
      - disable_strategy
      - kernel_module_usb-storage_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

    - name: Ensure kernel module 'usb-storage' is blacklisted
      lineinfile:
        create: true
        dest: /etc/modprobe.d/usb-storage.conf
        regexp: ^blacklist usb-storage$
        line: blacklist usb-storage
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020100
      - NIST-800-171-3.1.21
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - PCI-DSSv4-3.4.2
      - disable_strategy
      - kernel_module_usb-storage_disabled
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required

Group Restrict Partition Mount Options Group contains 14 rules
[ref] System partitions can be mounted with certain options that limit what files on those partitions can do. These options are set in the `/etc/fstab` configuration file, and can be used to make certain types of malicious behavior more difficult.

#### Rule Add nodev Option to /dev/shm [ref]

The `nodev` mount option can be used to prevent creation of device files in `/dev/shm`. Legitimate character and block devices should not exist within temporary directories like `/dev/shm`. Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/dev/shm`.
Rationale: | The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_dev_shm_nodev

Identifiers and References

References: 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, OL07-00-021024, SV-221747r853676_rule

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    function perform_remediation {

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /dev/shm)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="tmpfs"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
        fi

        if mkdir -p "/dev/shm"; then
            if mountpoint -q "/dev/shm"; then
                mount -o remount --target "/dev/shm"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nodev Option to /dev/shm: Check information associated to mountpoint'
      command: findmnt  '/dev/shm'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /dev/shm: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /dev/shm: If /dev/shm not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /dev/shm
        - tmpfs
        - tmpfs
        - defaults
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ("" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /dev/shm: Make sure nodev option is part of the to /dev/shm
        options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
          }) }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - mount_info is defined and "nodev" not in mount_info.options
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /dev/shm: Ensure /dev/shm is mounted with nodev option'
      mount:
        path: /dev/shm
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("" |
        length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nodev
      - no_reboot_needed

#### Rule Add noexec Option to /dev/shm [ref]

The `noexec` mount option can be used to prevent binaries from being executed out of `/dev/shm`. It can be dangerous to allow the execution of binaries from world-writable temporary storage directories such as `/dev/shm`. Add the `noexec` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/dev/shm`.
Rationale: | Allowing users to execute binaries from world-writable directories such as `/dev/shm` can expose the system to potential compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_dev_shm_noexec

Identifiers and References

References: 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, OL07-00-021024, SV-221747r853676_rule

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    function perform_remediation {

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /dev/shm)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="tmpfs"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "noexec"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
        fi

        if mkdir -p "/dev/shm"; then
            if mountpoint -q "/dev/shm"; then
                mount -o remount --target "/dev/shm"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add noexec Option to /dev/shm: Check information associated to mountpoint'
      command: findmnt  '/dev/shm'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /dev/shm: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /dev/shm: If /dev/shm not mounted, craft mount_info
        manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /dev/shm
        - tmpfs
        - tmpfs
        - defaults
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ("" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /dev/shm: Make sure noexec option is part of the to
        /dev/shm options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
          }) }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - mount_info is defined and "noexec" not in mount_info.options
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /dev/shm: Ensure /dev/shm is mounted with noexec option'
      mount:
        path: /dev/shm
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("" |
        length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_noexec
      - no_reboot_needed

#### Rule Add nosuid Option to /dev/shm [ref]

The `nosuid` mount option can be used to prevent execution of setuid programs in `/dev/shm`. The SUID and SGID permissions should not be required in these world-writable directories. Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/dev/shm`.
Rationale: | The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_dev_shm_nosuid

Identifiers and References

References: 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, OL07-00-021024, SV-221747r853676_rule

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    function perform_remediation {

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /dev/shm)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="tmpfs"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo "tmpfs /dev/shm tmpfs defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
        fi

        if mkdir -p "/dev/shm"; then
            if mountpoint -q "/dev/shm"; then
                mount -o remount --target "/dev/shm"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nosuid Option to /dev/shm: Check information associated to mountpoint'
      command: findmnt  '/dev/shm'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /dev/shm: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /dev/shm: If /dev/shm not mounted, craft mount_info
        manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /dev/shm
        - tmpfs
        - tmpfs
        - defaults
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ("" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /dev/shm: Make sure nosuid option is part of the to
        /dev/shm options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
          }) }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - mount_info is defined and "nosuid" not in mount_info.options
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /dev/shm: Ensure /dev/shm is mounted with nosuid option'
      mount:
        path: /dev/shm
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("" |
        length == 0)
      tags:
      - DISA-STIG-OL07-00-021024
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_dev_shm_nosuid
      - no_reboot_needed

#### Rule Add nodev Option to /home [ref]

The `nodev` mount option can be used to prevent device files from being created in `/home`. Legitimate character and block devices should exist only in the `/dev` directory on the root partition or within chroot jails built for system services. Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/home`.
Rationale: | The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_home_nodev
Identifiers and References | References: BP28(R12), SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/home" > /dev/null || findmnt --fstab "/home" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/home")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/home' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /home in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /home)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /home  defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
        fi

        if mkdir -p "/home"; then
            if mountpoint -q "/home"; then
                mount -o remount --target "/home"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /home --mountoptions="nodev"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nodev Option to /home: Check information associated to mountpoint'
      command: findmnt --fstab '/home'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/home" in ansible_mounts | map(attribute="mount") | list )
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - mount_option_home_nodev
      - no_reboot_needed
      - unknown_severity

    - name: 'Add nodev Option to /home: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/home" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - mount_option_home_nodev
      - no_reboot_needed
      - unknown_severity

    - name: 'Add nodev Option to /home: If /home not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /home
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/home" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - mount_option_home_nodev
      - no_reboot_needed
      - unknown_severity

    - name: 'Add nodev Option to /home: Make sure nodev option is part of the to /home
        options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/home" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "nodev" not in mount_info.options
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - mount_option_home_nodev
      - no_reboot_needed
      - unknown_severity

    - name: 'Add nodev Option to /home: Ensure /home is mounted with nodev option'
      mount:
        path: /home
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/home" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - mount_option_home_nodev
      - no_reboot_needed
      - unknown_severity

#### Rule Add nosuid Option to /home [ref]

The `nosuid` mount option can be used to prevent execution of setuid programs in `/home`. The SUID and SGID permissions should not be required in these user data directories. Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/home`.
Warning: OVAL looks for partitions whose mount point is a substring of any interactive user's home directory and validates that noexec option is there. Because of this, there could be false negatives when several partitions share a base substring. For example, if there is a home directory in `/var/tmp/user1` and there are partitions mounted in `/var` and `/var/tmp`. The noexec option is only expected in `/var/tmp`, but OVAL will check both.
Bash remediation uses the `df` command to find out the partition where the home directory is mounted. However, if the directory doesn't exist the remediation won't be applied.

Rationale: | The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from user home directory partitions.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_home_nosuid

Identifiers and References

References: BP28(R28), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154, SRG-OS-000480-GPOS-00227, OL07-00-021000, SV-221741r603801_rule

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    function perform_remediation (){

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" $1)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " $1  defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
        fi

        if mkdir -p "$1"; then
            if mountpoint -q "$1"; then
                mount -o remount --target "$1"
            fi
        fi
    }

    readarray -t home_directories  < \
        <(awk -F':' '{if ($3>=1000 && $3!= 65534) print $6}' /etc/passwd )

    for home_directory in "${home_directories[@]}"
    do
        if [ -d $home_directory ]; then
            fstab_mount_point=$(df $home_directory | awk '/^\/dev/ {print $6}')
            if  ! grep -qP "^/$|^/lib$|^/opt$|^/usr$|^/bin$|^/sbin$|^/boot$|^/dev$|^/proc$" <<< $fstab_mount_point
            then
                perform_remediation "$fstab_mount_point"
            fi
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

#### Rule Add nodev Option to Removable Media Partitions [ref]

The `nodev` mount option prevents files from being interpreted as character or block devices. Legitimate character and block devices should exist only in the `/dev` directory on the root partition or within chroot jails built for system services. Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of any removable media partitions.
Rationale: | The only legitimate location for device files is the `/dev` directory located on the root partition. An exception to this is chroot jails, and it is not advised to set `nodev` on partitions which contain their root filesystems.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_nodev_removable_partitions

Identifiers and References

References: 11, 12, 13, 14, 16, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.03, DSS06.06, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.7.1.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, A.9.2.1, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.AC-3, PR.AC-6, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_removable_partition='(N/A)'

    device_regex="^\s*$var_removable_partition\s\+"
    mount_option="nodev"

    if grep -q $device_regex /etc/fstab ; then
        previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
        sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
    else
        echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_removable_partition # promote to variable
      set_fact:
        var_removable_partition: !!str (N/A)
      tags:
        - always

    - name: Ensure permission nodev are set on var_removable_partition
      lineinfile:
        path: /etc/fstab
        regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
        backrefs: true
        line: \1 \2 \3 \4,nodev \5
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_nodev_removable_partitions
      - no_reboot_needed

#### Rule Add noexec Option to Removable Media Partitions [ref]

The `noexec` mount option prevents the direct execution of binaries on the mounted filesystem. Preventing the direct execution of binaries from removable media (such as a USB key) provides a defense against malicious software that may be present on such untrusted media. Add the `noexec` option to the fourth column of `/etc/fstab` for the line which controls mounting of any removable media partitions.

Rationale: | Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_noexec_removable_partitions

Identifiers and References

References: 11, 12, 13, 14, 16, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.03, DSS06.06, CCI-000087, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.7.1.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, A.9.2.1, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.AC-3, PR.AC-6, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_removable_partition='(N/A)'

    device_regex="^\s*$var_removable_partition\s\+"
    mount_option="noexec"

    if grep -q $device_regex /etc/fstab ; then
        previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
        sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
    else
        echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_removable_partition # promote to variable
      set_fact:
        var_removable_partition: !!str (N/A)
      tags:
        - always

    - name: Ensure permission noexec are set on var_removable_partition
      lineinfile:
        path: /etc/fstab
        regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
        backrefs: true
        line: \1 \2 \3 \4,noexec \5
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_noexec_removable_partitions
      - no_reboot_needed

#### Rule Add nosuid Option to Removable Media Partitions [ref]

The `nosuid` mount option prevents set-user-identifier (SUID) and set-group-identifier (SGID) permissions from taking effect. These permissions allow users to execute binaries with the same permissions as the owner and group of the file respectively. Users should not be allowed to introduce SUID and SGID files into the system via partitions mounted from removeable media. Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of any removable media partitions.

Rationale: | The presence of SUID and SGID executables should be tightly controlled. Allowing users to introduce SUID or SGID binaries from partitions mounted off of removable media would allow them to introduce their own highly-privileged programs.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_nosuid_removable_partitions

Identifiers and References

References: 11, 12, 13, 14, 15, 16, 18, 3, 5, 8, 9, APO01.06, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.06, DSS05.07, DSS06.02, DSS06.03, DSS06.06, CCI-000366, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.AC-3, PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000480-GPOS-00227, OL07-00-021010, SV-221742r603260_rule

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_removable_partition='(N/A)'

    device_regex="^\s*$var_removable_partition\s\+"
    mount_option="nosuid"

    if grep -q $device_regex /etc/fstab ; then
        previous_opts=$(grep $device_regex /etc/fstab | awk '{print $4}')
        sed -i "s|\($device_regex.*$previous_opts\)|\1,$mount_option|" /etc/fstab
    else
        echo "Not remediating, because there is no record of $var_removable_partition in /etc/fstab" >&2
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_removable_partition # promote to variable
      set_fact:
        var_removable_partition: !!str (N/A)
      tags:
        - always

    - name: Ensure permission nosuid are set on var_removable_partition
      lineinfile:
        path: /etc/fstab
        regexp: ^\s*({{ var_removable_partition }})\s+([^\s]*)\s+([^\s]*)\s+([^\s]*)(.*)$
        backrefs: true
        line: \1 \2 \3 \4,nosuid \5
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021010
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_nosuid_removable_partitions
      - no_reboot_needed

#### Rule Add nodev Option to /tmp [ref]

The `nodev` mount option can be used to prevent device files from being created in `/tmp`. Legitimate character and block devices should not exist within temporary directories like `/tmp`. Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/tmp`.
Rationale: | The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_tmp_nodev

Identifiers and References

References: BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/tmp" > /dev/null || findmnt --fstab "/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /tmp  defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
        fi

        if mkdir -p "/tmp"; then
            if mountpoint -q "/tmp"; then
                mount -o remount --target "/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /tmp --mountoptions="nodev"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nodev Option to /tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /tmp: If /tmp not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /tmp: Make sure nodev option is part of the to /tmp options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "nodev" not in mount_info.options
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /tmp: Ensure /tmp is mounted with nodev option'
      mount:
        path: /tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nodev
      - no_reboot_needed

#### Rule Add noexec Option to /tmp [ref]

The `noexec` mount option can be used to prevent binaries from being executed out of `/tmp`. Add the `noexec` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/tmp`.
Rationale: | Allowing users to execute binaries from world-writable directories such as `/tmp` should never be necessary in normal operation and can expose the system to potential compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_tmp_noexec

Identifiers and References

References: BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/tmp" > /dev/null || findmnt --fstab "/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /tmp  defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "noexec"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
        fi

        if mkdir -p "/tmp"; then
            if mountpoint -q "/tmp"; then
                mount -o remount --target "/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /tmp --mountoptions="noexec"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add noexec Option to /tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /tmp: If /tmp not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /tmp: Make sure noexec option is part of the to /tmp
        options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "noexec" not in mount_info.options
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /tmp: Ensure /tmp is mounted with noexec option'
      mount:
        path: /tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_noexec
      - no_reboot_needed

#### Rule Add nosuid Option to /tmp [ref]

The `nosuid` mount option can be used to prevent execution of setuid programs in `/tmp`. The SUID and SGID permissions should not be required in these world-writable directories. Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/tmp`.
Rationale: | The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_tmp_nosuid

Identifiers and References

References: BP28(R12), 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-001764, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-6, AC-6(1), MP-7, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/tmp" > /dev/null || findmnt --fstab "/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /tmp  defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
        fi

        if mkdir -p "/tmp"; then
            if mountpoint -q "/tmp"; then
                mount -o remount --target "/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /tmp --mountoptions="nosuid"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nosuid Option to /tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /tmp: If /tmp not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /tmp: Make sure nosuid option is part of the to /tmp
        options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "nosuid" not in mount_info.options
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /tmp: Ensure /tmp is mounted with nosuid option'
      mount:
        path: /tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-MP-7
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_tmp_nosuid
      - no_reboot_needed

#### Rule Add nodev Option to /var/tmp [ref]

The `nodev` mount option can be used to prevent device files from being created in `/var/tmp`. Legitimate character and block devices should not exist within temporary directories like `/var/tmp`. Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/var/tmp`.
Rationale: | The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_var_tmp_nodev
Identifiers and References | References: BP28(R12), CCI-001764, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/var/tmp" > /dev/null || findmnt --fstab "/var/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/var/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /var/tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /var/tmp  defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
        fi

        if mkdir -p "/var/tmp"; then
            if mountpoint -q "/var/tmp"; then
                mount -o remount --target "/var/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /var/tmp --mountoptions="nodev"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nodev Option to /var/tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/var/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/var/tmp" in ansible_mounts | map(attribute="mount") | list
        )
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /var/tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /var/tmp: If /var/tmp not mounted, craft mount_info manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /var/tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /var/tmp: Make sure nodev option is part of the to /var/tmp
        options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nodev''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "nodev" not in mount_info.options
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nodev
      - no_reboot_needed

    - name: 'Add nodev Option to /var/tmp: Ensure /var/tmp is mounted with nodev option'
      mount:
        path: /var/tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nodev
      - no_reboot_needed

#### Rule Add noexec Option to /var/tmp [ref]

The `noexec` mount option can be used to prevent binaries from being executed out of `/var/tmp`. Add the `noexec` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/var/tmp`.
Rationale: | Allowing users to execute binaries from world-writable directories such as `/var/tmp` should never be necessary in normal operation and can expose the system to potential compromise.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_var_tmp_noexec
Identifiers and References | References: BP28(R12), CCI-001764, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/var/tmp" > /dev/null || findmnt --fstab "/var/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/var/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /var/tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|noexec)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /var/tmp  defaults,${previous_mount_opts}noexec 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "noexec"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,noexec|" /etc/fstab
        fi

        if mkdir -p "/var/tmp"; then
            if mountpoint -q "/var/tmp"; then
                mount -o remount --target "/var/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /var/tmp --mountoptions="noexec"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add noexec Option to /var/tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/var/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/var/tmp" in ansible_mounts | map(attribute="mount") | list
        )
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /var/tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /var/tmp: If /var/tmp not mounted, craft mount_info
        manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /var/tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /var/tmp: Make sure noexec option is part of the to
        /var/tmp options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',noexec''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "noexec" not in mount_info.options
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_noexec
      - no_reboot_needed

    - name: 'Add noexec Option to /var/tmp: Ensure /var/tmp is mounted with noexec option'
      mount:
        path: /var/tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_noexec
      - no_reboot_needed

#### Rule Add nosuid Option to /var/tmp [ref]

The `nosuid` mount option can be used to prevent execution of setuid programs in `/var/tmp`. The SUID and SGID permissions should not be required in these world-writable directories. Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of `/var/tmp`.
Rationale: | The presence of SUID and SGID executables should be tightly controlled. Users should not be able to execute SUID or SGID binaries from temporary storage partitions.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_var_tmp_nosuid
Identifiers and References | References: BP28(R12), CCI-001764, SRG-OS-000368-GPOS-00154

Remediation Shell script ⇲

Reboot: | false

    # Remediation is applicable only in certain platforms
    if ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && findmnt --kernel "/var/tmp" > /dev/null || findmnt --fstab "/var/tmp" > /dev/null ); then

    function perform_remediation {

            mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" "/var/tmp")"

        grep "$mount_point_match_regexp" -q /etc/fstab \
            || { echo "The mount point '/var/tmp' is not even in /etc/fstab, so we can't set up mount options" >&2;
                    echo "Not remediating, because there is no record of /var/tmp in /etc/fstab" >&2; return 1; }

        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" /var/tmp)"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type=""
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " /var/tmp  defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
        fi

        if mkdir -p "/var/tmp"; then
            if mountpoint -q "/var/tmp"; then
                mount -o remount --target "/var/tmp"
            fi
        fi
    }

    perform_remediation

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | enable

    part /var/tmp --mountoptions="nosuid"

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | high
Reboot: | false
Strategy: | configure

    - name: 'Add nosuid Option to /var/tmp: Check information associated to mountpoint'
      command: findmnt --fstab '/var/tmp'
      register: device_name
      failed_when: device_name.rc > 1
      changed_when: false
      when: ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman",
        "container"] and "/var/tmp" in ansible_mounts | map(attribute="mount") | list
        )
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /var/tmp: Create mount_info dictionary variable'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - '{{ device_name.stdout_lines[0].split() | list | lower }}'
      - '{{ device_name.stdout_lines[1].split() | list }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - device_name.stdout is defined and device_name.stdout_lines is defined
      - (device_name.stdout | length > 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /var/tmp: If /var/tmp not mounted, craft mount_info
        manually'
      set_fact:
        mount_info: '{{ mount_info|default({})|combine({item.0: item.1}) }}'
      with_together:
      - - target
        - source
        - fstype
        - options
      - - /var/tmp
        - ''
        - ''
        - defaults
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - ("--fstab" | length == 0)
      - (device_name.stdout | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /var/tmp: Make sure nosuid option is part of the to
        /var/tmp options'
      set_fact:
        mount_info: '{{ mount_info | combine( {''options'':''''~mount_info.options~'',nosuid''
          }) }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - mount_info is defined and "nosuid" not in mount_info.options
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nosuid
      - no_reboot_needed

    - name: 'Add nosuid Option to /var/tmp: Ensure /var/tmp is mounted with nosuid option'
      mount:
        path: /var/tmp
        src: '{{ mount_info.source }}'
        opts: '{{ mount_info.options }}'
        state: mounted
        fstype: '{{ mount_info.fstype }}'
      when:
      - ( ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
        and "/var/tmp" in ansible_mounts | map(attribute="mount") | list )
      - (device_name.stdout is defined and (device_name.stdout | length > 0)) or ("--fstab"
        | length == 0)
      tags:
      - configure_strategy
      - high_disruption
      - low_complexity
      - medium_severity
      - mount_option_var_tmp_nosuid
      - no_reboot_needed

Group Restrict Programs from Dangerous Execution Patterns Group contains 3 groups and 9 rules
[ref] The recommendations in this section are designed to ensure that the system's features to protect against potentially dangerous program execution are activated. These protections are applied at the system initialization or kernel level, and defend against certain types of badly-configured or compromised programs.
Group Disable Core Dumps Group contains 2 rules

[ref] A core dump file is the memory image of an executable program when it was terminated by the operating system due to errant behavior. In most cases, only software developers legitimately need to access these files. The core dump files may also contain sensitive information, or unnecessarily occupy large amounts of disk space.
Once a hard limit is set in `/etc/security/limits.conf`, or to a file within the `/etc/security/limits.d/` directory, a user cannot increase that limit within his or her own session. If access to core dumps is required, consider restricting them to only certain users or groups. See the `limits.conf` man page for more information.
The core dumps of setuid programs are further protected. The `sysctl` variable `fs.suid_dumpable` controls whether the kernel allows core dumps from these programs at all. The default value of 0 is recommended.

#### Rule Disable Core Dumps for All Users [ref]

To disable core dumps for all users, add the following line to `/etc/security/limits.conf`, or to a file within the `/etc/security/limits.d/` directory:

    *     hard   core    0

Rationale: | A core dump includes a memory image taken at the time the operating system terminates an application. The memory image could contain sensitive data and is generally useful only for developers trying to debug problems.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_disable_users_coredumps
Identifiers and References | References: 1, 12, 13, 15, 16, 2, 7, 8, APO13.01, BAI04.04, DSS01.03, DSS03.05, DSS05.07, CCI-000366, SR 6.2, SR 7.1, SR 7.2, A.12.1.3, A.17.2.1, CM-6, SC-7(10), DE.CM-1, PR.DS-4, 3.3.1, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q pam; then

    SECURITY_LIMITS_FILE="/etc/security/limits.conf"

    if grep -qE '^\s*\*\s+hard\s+core' $SECURITY_LIMITS_FILE; then
            sed -ri 's/(hard\s+core\s+)[[:digit:]]+/\1 0/' $SECURITY_LIMITS_FILE
    else
            echo "*     hard   core    0" >> $SECURITY_LIMITS_FILE
    fi

    if ls /etc/security/limits.d/*.conf > /dev/null; then
            sed -ri '/^\s*\*\s+hard\s+core/d' /etc/security/limits.d/*.conf
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6
      - NIST-800-53-SC-7(10)
      - PCI-DSSv4-3.3.1
      - disable_users_coredumps
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Disable core dumps with limits
      lineinfile:
        dest: /etc/security/limits.conf
        regexp: ^[^#].*core
        line: '*        hard       core      0'
        create: true
      when: '"pam" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6
      - NIST-800-53-SC-7(10)
      - PCI-DSSv4-3.3.1
      - disable_users_coredumps
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Disable Core Dumps for SUID programs [ref]

To set the runtime status of the `fs.suid_dumpable` kernel parameter, run the following command:

    $ sudo sysctl -w fs.suid_dumpable=0

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    fs.suid_dumpable = 0

Rationale: | The core dump of a setuid program is more likely to contain sensitive data, as the program itself runs with greater privileges than the user who initiated execution of the program. Disabling the ability for any setuid program to write a core file decreases the risk of unauthorized access of such data.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_fs_suid_dumpable
Identifiers and References | References: BP28(R23), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), 3.3.1

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of fs.suid_dumpable from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*fs.suid_dumpable.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "fs.suid_dumpable" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for fs.suid_dumpable
    #
    /sbin/sysctl -q -n -w fs.suid_dumpable="0"

    #
    # If fs.suid_dumpable present in /etc/sysctl.conf, change value to "0"
    #	else, add "fs.suid_dumpable = 0" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^fs.suid_dumpable")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "0"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^fs.suid_dumpable\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^fs.suid_dumpable\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*fs.suid_dumpable.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_suid_dumpable

    - name: Comment out any occurrences of fs.suid_dumpable from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*fs.suid_dumpable
        replace: '#fs.suid_dumpable'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_suid_dumpable

    - name: Ensure sysctl fs.suid_dumpable is set to 0
      sysctl:
        name: fs.suid_dumpable
        value: '0'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_fs_suid_dumpable

Group Enable ExecShield Group contains 2 rules

[ref] ExecShield describes kernel features that provide protection against exploitation of memory corruption errors such as buffer overflows. These features include random placement of the stack and other memory regions, prevention of execution in memory that should only hold data, and special handling of text buffers. These protections are enabled by default on 32-bit systems and controlled through `sysctl` variables `kernel.exec-shield` and `kernel.randomize_va_space`. On the latest 64-bit systems, `kernel.exec-shield` cannot be enabled or disabled with `sysctl`.

#### Rule Restrict Exposed Kernel Pointer Addresses Access [ref]

To set the runtime status of the `kernel.kptr_restrict` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.kptr_restrict=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    kernel.kptr_restrict = 1

Rationale:

Exposing kernel pointers (through procfs or `seq_printf()`) exposes kernel writeable structures which may contain functions pointers. If a write vulnerability occurs in the kernel, allowing write access to any of this structure, the kernel can be compromised. This option disallow any program without the CAP_SYSLOG capability to get the addresses of kernel pointers by replacing them with 0.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_kptr_restrict

Identifiers and References

References: BP28(R23), CCI-002824, CCI-000366, CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), SC-30(5), CM-6(a), SRG-OS-000132-GPOS-00067, SRG-OS-000433-GPOS-00192, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of kernel.kptr_restrict from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*kernel.kptr_restrict.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "kernel.kptr_restrict" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    sysctl_kernel_kptr_restrict_value='1'

    #
    # Set runtime for kernel.kptr_restrict
    #
    /sbin/sysctl -q -n -w kernel.kptr_restrict="$sysctl_kernel_kptr_restrict_value"

    #
    # If kernel.kptr_restrict present in /etc/sysctl.conf, change value to appropriate value
    #	else, add "kernel.kptr_restrict = value" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.kptr_restrict")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "$sysctl_kernel_kptr_restrict_value"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^kernel.kptr_restrict\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^kernel.kptr_restrict\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*kernel.kptr_restrict.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - NIST-800-53-SC-30(5)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kptr_restrict

    - name: Comment out any occurrences of kernel.kptr_restrict from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*kernel.kptr_restrict
        replace: '#kernel.kptr_restrict'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - NIST-800-53-SC-30(5)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kptr_restrict
    - name: XCCDF Value sysctl_kernel_kptr_restrict_value # promote to variable
      set_fact:
        sysctl_kernel_kptr_restrict_value: !!str 1
      tags:
        - always

    - name: Ensure sysctl kernel.kptr_restrict is set
      sysctl:
        name: kernel.kptr_restrict
        value: '{{ sysctl_kernel_kptr_restrict_value }}'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - NIST-800-53-SC-30(5)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kptr_restrict

#### Rule Enable Randomized Layout of Virtual Address Space [ref]

To set the runtime status of the `kernel.randomize_va_space` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.randomize_va_space=2

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    kernel.randomize_va_space = 2

Rationale: | Address space layout randomization (ASLR) makes it more difficult for an attacker to predict the location of attack code they have introduced into a process's address space during an attempt at exploitation. Additionally, ASLR makes it more difficult for an attacker to know the location of existing code in order to re-purpose it using return oriented programming (ROP) techniques.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_randomize_va_space

Identifiers and References

References: BP28(R23), 3.1.7, CCI-000366, CCI-002824, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), CIP-002-5 R1.1, CIP-002-5 R1.2, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 4.1, CIP-004-6 4.2, CIP-004-6 R2.2.3, CIP-004-6 R2.2.4, CIP-004-6 R2.3, CIP-004-6 R4, CIP-005-6 R1, CIP-005-6 R1.1, CIP-005-6 R1.2, CIP-007-3 R3, CIP-007-3 R3.1, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.1.3, CIP-007-3 R5.2.1, CIP-007-3 R5.2.3, CIP-007-3 R8.4, CIP-009-6 R.1.1, CIP-009-6 R4, SC-30, SC-30(2), CM-6(a), Req-2.2.1, 3.3.1, SRG-OS-000433-GPOS-00193, SRG-OS-000480-GPOS-00227, SRG-APP-000450-CTR-001105, OL07-00-040201, SV-221846r880630_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of kernel.randomize_va_space from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*kernel.randomize_va_space.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "kernel.randomize_va_space" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for kernel.randomize_va_space
    #
    /sbin/sysctl -q -n -w kernel.randomize_va_space="2"

    #
    # If kernel.randomize_va_space present in /etc/sysctl.conf, change value to "2"
    #	else, add "kernel.randomize_va_space = 2" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.randomize_va_space")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "2"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^kernel.randomize_va_space\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^kernel.randomize_va_space\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*kernel.randomize_va_space.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040201
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - PCI-DSS-Req-2.2.1
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_randomize_va_space

    - name: Comment out any occurrences of kernel.randomize_va_space from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*kernel.randomize_va_space
        replace: '#kernel.randomize_va_space'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040201
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - PCI-DSS-Req-2.2.1
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_randomize_va_space

    - name: Ensure sysctl kernel.randomize_va_space is set to 2
      sysctl:
        name: kernel.randomize_va_space
        value: '2'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040201
      - NIST-800-171-3.1.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-30
      - NIST-800-53-SC-30(2)
      - PCI-DSS-Req-2.2.1
      - PCI-DSSv4-3.3.1
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_randomize_va_space

Group Memory Poisoning Group contains 2 rules
[ref] Memory Poisoning consists of writing a special value to uninitialized or freed memory. Poisoning can be used as a mechanism to prevent leak of information and detection of corrupted memory.

#### Rule Enable page allocator poisoning [ref]

To enable poisoning of free pages, add the argument `page_poison=1` to the default GRUB 2 command line for the Linux operating system. To ensure that `page_poison=1` is added as a kernel command line argument to newly installed kernels, add `page_poison=1` to the default Grub2 command line for Linux operating systems. Modify the line within `/etc/default/grub` as shown below:

    GRUB_CMDLINE_LINUX="... page_poison=1 ..."

Run the following command to update command line for already installed kernels:

    # grubby --update-kernel=ALL --args="page_poison=1"

Rationale: | Poisoning writes an arbitrary value to freed pages, so any modification or reference to that page after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. Also prevents leak of data and detection of corrupted memory.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_page_poison_argument
Identifiers and References | References: BP28(R8), CCI-001084, CM-6(a), SRG-OS-000480-GPOS-00227, SRG-OS-000134-GPOS-00068

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    # Correct the form of default kernel command line in GRUB
    if grep -q '^\s*GRUB_CMDLINE_LINUX=.*page_poison=.*"'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an page_poison= arg already exists
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)page_poison=[^[:space:]]\+\(.*\"\)/\1page_poison=1\2/"  '/etc/default/grub'
    # Add to already existing GRUB_CMDLINE_LINUX parameters
    elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
           # no page_poison=arg is present, append it
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 page_poison=1\"/"  '/etc/default/grub'
    # Add GRUB_CMDLINE_LINUX parameters line
    else
           echo "GRUB_CMDLINE_LINUX=\"page_poison=1\"" >> '/etc/default/grub'
    fi
    grubby --update-kernel=ALL --args=page_poison=1

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | medium
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check page_poison argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=.*page_poison=' /etc/default/grub
      failed_when: false
      register: argcheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check page_poison argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
      failed_when: false
      register: linecheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for  in /etc/audit/audit.rules
      ansible.builtin.lineinfile:
        line: GRUB_CMDLINE_LINUX="page_poison=1 "
        state: present
        dest: /etc/default/grub
        create: true
        mode: '0644'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc != 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Replace existing page_poison argument
      replace:
        path: /etc/default/grub
        regexp: page_poison=\w+
        replace: page_poison=1
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc == 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add page_poison argument
      replace:
        path: /etc/default/grub
        regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
        replace: \1 page_poison=1"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Update grub defaults and the bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="page_poison=1"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_page_poison_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

Remediation OSBuild Blueprint snippet ⇲

    [customizations.kernel]
    append = "page_poison=1"

#### Rule Enable SLUB/SLAB allocator poisoning [ref]

To enable poisoning of SLUB/SLAB objects, add the argument `slub_debug=P` to the default GRUB 2 command line for the Linux operating system. To ensure that `slub_debug=P` is added as a kernel command line argument to newly installed kernels, add `slub_debug=P` to the default Grub2 command line for Linux operating systems. Modify the line within `/etc/default/grub` as shown below:

    GRUB_CMDLINE_LINUX="... slub_debug=P ..."

Run the following command to update command line for already installed kernels:

    # grubby --update-kernel=ALL --args="slub_debug=P"

Rationale: | Poisoning writes an arbitrary value to freed objects, so any modification or reference to that object after being freed or before being initialized will be detected and prevented. This prevents many types of use-after-free vulnerabilities at little performance cost. Also prevents leak of data and detection of corrupted memory.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_slub_debug_argument
Identifiers and References | References: BP28(R8), CCI-001084, CM-6(a), SRG-OS-000433-GPOS-00192, SRG-OS-000134-GPOS-00068

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    var_slub_debug_options='P'

    # Correct the form of default kernel command line in GRUB
    if grep -q '^\s*GRUB_CMDLINE_LINUX=.*slub_debug=.*"'  '/etc/default/grub' ; then
           # modify the GRUB command-line if an slub_debug= arg already exists
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)slub_debug=[^[:space:]]\+\(.*\"\)/\1slub_debug=$var_slub_debug_options\2/"  '/etc/default/grub'
    # Add to already existing GRUB_CMDLINE_LINUX parameters
    elif grep -q '^\s*GRUB_CMDLINE_LINUX='  '/etc/default/grub' ; then
           # no slub_debug=arg is present, append it
           sed -i "s/\(^\s*GRUB_CMDLINE_LINUX=\".*\)\"/\1 slub_debug=$var_slub_debug_options\"/"  '/etc/default/grub'
    # Add GRUB_CMDLINE_LINUX parameters line
    else
           echo "GRUB_CMDLINE_LINUX=\"slub_debug=$var_slub_debug_options\"" >> '/etc/default/grub'
    fi
    grubby --update-kernel=ALL --args=slub_debug=$var_slub_debug_options

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | medium
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy
    - name: XCCDF Value var_slub_debug_options # promote to variable
      set_fact:
        var_slub_debug_options: !!str P
      tags:
        - always

    - name: Check slub_debug argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=.*slub_debug=' /etc/default/grub
      failed_when: false
      register: argcheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Check slub_debug argument exists
      command: grep '^\s*GRUB_CMDLINE_LINUX=' /etc/default/grub
      failed_when: false
      register: linecheck
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add watch rule for  in /etc/audit/audit.rules
      ansible.builtin.lineinfile:
        line: GRUB_CMDLINE_LINUX="slub_debug={{ var_slub_debug_options }} "
        state: present
        dest: /etc/default/grub
        create: true
        mode: '0644'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc != 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Replace existing slub_debug argument
      replace:
        path: /etc/default/grub
        regexp: slub_debug=\w+
        replace: slub_debug={{ var_slub_debug_options }}
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc == 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Add slub_debug argument
      replace:
        path: /etc/default/grub
        regexp: (^\s*GRUB_CMDLINE_LINUX=.*)"
        replace: \1 slub_debug={{ var_slub_debug_options }}"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - argcheck.rc != 0 and linecheck.rc == 0
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

    - name: Update grub defaults and the bootloader menu
      command: /sbin/grubby --update-kernel=ALL --args="slub_debug={{ var_slub_debug_options
        }}"
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - grub2_slub_debug_argument
      - low_disruption
      - medium_complexity
      - medium_severity
      - reboot_required
      - restrict_strategy

Remediation OSBuild Blueprint snippet ⇲

    [customizations.kernel]
    append = "slub_debug=P"

#### Rule Restrict Access to Kernel Message Buffer [ref]

To set the runtime status of the `kernel.dmesg_restrict` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.dmesg_restrict=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    kernel.dmesg_restrict = 1

Rationale: | Unprivileged access to the kernel syslog can expose sensitive kernel address information.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_dmesg_restrict
Identifiers and References | References: BP28(R23), 3.1.5, CCI-001090, CCI-001314, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), SI-11(a), SI-11(b), SRG-OS-000132-GPOS-00067, SRG-OS-000138-GPOS-00069, SRG-APP-000243-CTR-000600, OL07-00-010375, SV-255901r880627_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of kernel.dmesg_restrict from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*kernel.dmesg_restrict.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "kernel.dmesg_restrict" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for kernel.dmesg_restrict
    #
    /sbin/sysctl -q -n -w kernel.dmesg_restrict="1"

    #
    # If kernel.dmesg_restrict present in /etc/sysctl.conf, change value to "1"
    #	else, add "kernel.dmesg_restrict = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.dmesg_restrict")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^kernel.dmesg_restrict\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^kernel.dmesg_restrict\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*kernel.dmesg_restrict.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010375
      - NIST-800-171-3.1.5
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - disable_strategy
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required
      - sysctl_kernel_dmesg_restrict

    - name: Comment out any occurrences of kernel.dmesg_restrict from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*kernel.dmesg_restrict
        replace: '#kernel.dmesg_restrict'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010375
      - NIST-800-171-3.1.5
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - disable_strategy
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required
      - sysctl_kernel_dmesg_restrict

    - name: Ensure sysctl kernel.dmesg_restrict is set to 1
      sysctl:
        name: kernel.dmesg_restrict
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-010375
      - NIST-800-171-3.1.5
      - NIST-800-53-SI-11(a)
      - NIST-800-53-SI-11(b)
      - disable_strategy
      - low_complexity
      - low_severity
      - medium_disruption
      - reboot_required
      - sysctl_kernel_dmesg_restrict

#### Rule Disable Kernel Image Loading [ref]

To set the runtime status of the `kernel.kexec_load_disabled` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.kexec_load_disabled=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    kernel.kexec_load_disabled = 1

Rationale: | Disabling kexec_load allows greater control of the kernel memory. It makes it impossible to load another kernel image after it has been disabled.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_kexec_load_disabled
Identifiers and References | References: CCI-001749, CM-6, SRG-OS-000480-GPOS-00227, SRG-OS-000366-GPOS-00153

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of kernel.kexec_load_disabled from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*kernel.kexec_load_disabled.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "kernel.kexec_load_disabled" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for kernel.kexec_load_disabled
    #
    /sbin/sysctl -q -n -w kernel.kexec_load_disabled="1"

    #
    # If kernel.kexec_load_disabled present in /etc/sysctl.conf, change value to "1"
    #	else, add "kernel.kexec_load_disabled = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.kexec_load_disabled")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^kernel.kexec_load_disabled\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^kernel.kexec_load_disabled\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*kernel.kexec_load_disabled.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kexec_load_disabled

    - name: Comment out any occurrences of kernel.kexec_load_disabled from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*kernel.kexec_load_disabled
        replace: '#kernel.kexec_load_disabled'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kexec_load_disabled

    - name: Ensure sysctl kernel.kexec_load_disabled is set to 1
      sysctl:
        name: kernel.kexec_load_disabled
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_kexec_load_disabled

#### Rule Restrict usage of ptrace to descendant processes [ref]

To set the runtime status of the `kernel.yama.ptrace_scope` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.yama.ptrace_scope=1

To make sure that the setting is persistent, add the following line to a file in the directory `/etc/sysctl.d`:

    kernel.yama.ptrace_scope = 1

Rationale: | Unrestricted usage of ptrace allows compromised binaries to run ptrace on another processes of the user. Like this, the attacker can steal sensitive information from the target processes (e.g. SSH sessions, web browser, ...) without any additional assistance from the user (i.e. without resorting to phishing).
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sysctl_kernel_yama_ptrace_scope
Identifiers and References | References: BP28(R25), CCI-000366, SC-7(10), SRG-OS-000132-GPOS-00067, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Comment out any occurrences of kernel.yama.ptrace_scope from /etc/sysctl.d/*.conf files

    for f in /etc/sysctl.d/*.conf /run/sysctl.d/*.conf /usr/local/lib/sysctl.d/*.conf; do

      matching_list=$(grep -P '^(?!#).*[\s]*kernel.yama.ptrace_scope.*$' $f | uniq )
      if ! test -z "$matching_list"; then
        while IFS= read -r entry; do
          escaped_entry=$(sed -e 's|/|\\/|g' <<< "$entry")
          # comment out "kernel.yama.ptrace_scope" matches to preserve user data
          sed -i "s/^${escaped_entry}$/# &/g" $f
        done <<< "$matching_list"
      fi
    done

    #
    # Set sysctl config file which to save the desired value
    #

    SYSCONFIG_FILE="/etc/sysctl.conf"

    #
    # Set runtime for kernel.yama.ptrace_scope
    #
    /sbin/sysctl -q -n -w kernel.yama.ptrace_scope="1"

    #
    # If kernel.yama.ptrace_scope present in /etc/sysctl.conf, change value to "1"
    #	else, add "kernel.yama.ptrace_scope = 1" to /etc/sysctl.conf
    #

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^kernel.yama.ptrace_scope")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s = %s" "$stripped_key" "1"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^kernel.yama.ptrace_scope\\>" "${SYSCONFIG_FILE}"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^kernel.yama.ptrace_scope\\>.*/$escaped_formatted_output/gi" "${SYSCONFIG_FILE}"
    else
        if [[ -s "${SYSCONFIG_FILE}" ]] && [[ -n "$(tail -c 1 -- "${SYSCONFIG_FILE}" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "${SYSCONFIG_FILE}"
        fi
        printf '%s\n' "$formatted_output" >> "${SYSCONFIG_FILE}"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | true
Strategy: | disable

    - name: List /etc/sysctl.d/*.conf files
      find:
        paths:
        - /etc/sysctl.d/
        - /run/sysctl.d/
        - /usr/local/lib/sysctl.d/
        contains: ^[\s]*kernel.yama.ptrace_scope.*$
        patterns: '*.conf'
        file_type: any
      register: find_sysctl_d
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SC-7(10)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_yama_ptrace_scope

    - name: Comment out any occurrences of kernel.yama.ptrace_scope from config files
      replace:
        path: '{{ item.path }}'
        regexp: ^[\s]*kernel.yama.ptrace_scope
        replace: '#kernel.yama.ptrace_scope'
      loop: '{{ find_sysctl_d.files }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SC-7(10)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_yama_ptrace_scope

    - name: Ensure sysctl kernel.yama.ptrace_scope is set to 1
      sysctl:
        name: kernel.yama.ptrace_scope
        value: '1'
        sysctl_file: /etc/sysctl.conf
        state: present
        reload: true
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-SC-7(10)
      - disable_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - reboot_required
      - sysctl_kernel_yama_ptrace_scope

Group SELinux Group contains 1 group and 66 rules

[ref] SELinux is a feature of the Linux kernel which can be used to guard against misconfigured or compromised programs. SELinux enforces the idea that programs should be limited in what files they can access and what actions they can take.
The default SELinux policy, as configured on Oracle Linux 7, has been sufficiently developed and debugged that it should be usable on almost any system with minimal configuration and a small amount of system administrator training. This policy prevents system services - including most of the common network-visible services such as mail servers, FTP servers, and DNS servers - from accessing files which those services have no valid reason to access. This action alone prevents a huge amount of possible damage from network attacks against services, from trojaned software, and so forth.
This guide recommends that SELinux be enabled using the default (targeted) policy on every Oracle Linux 7 system, unless that system has unusual requirements which make a stronger policy appropriate. For more information on SELinux, see https://docs.oracle.com/en/operating-systems/oracle-linux/selinux/.

Group SELinux - Booleans Group contains 61 rules
[ref] Enable or Disable runtime customization of SELinux system policies without having to reload or recompile the SELinux policy.

#### Rule Disable the abrt_anon_write SELinux Boolean [ref]

By default, the SELinux boolean `abrt_anon_write` is disabled. If this setting is enabled, it should be disabled. To disable the `abrt_anon_write` SELinux boolean, run the following command:

    $ sudo setsebool -P abrt_anon_write off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_abrt_anon_write
Identifiers and References | References: 3.7.2

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_abrt_anon_write='false'

    setsebool -P abrt_anon_write $var_abrt_anon_write

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_abrt_anon_write # promote to variable
      set_fact:
        var_abrt_anon_write: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_anon_write

    - name: Set SELinux boolean abrt_anon_write accordingly
      seboolean:
        name: abrt_anon_write
        state: '{{ var_abrt_anon_write }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_anon_write

#### Rule Disable the abrt_handle_event SELinux Boolean [ref]

By default, the SELinux boolean `abrt_handle_event` is disabled. If this setting is enabled, it should be disabled. To disable the `abrt_handle_event` SELinux boolean, run the following command:

    $ sudo setsebool -P abrt_handle_event off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_abrt_handle_event
Identifiers and References | References: 3.7.2

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_abrt_handle_event='false'

    setsebool -P abrt_handle_event $var_abrt_handle_event

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_abrt_handle_event # promote to variable
      set_fact:
        var_abrt_handle_event: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_handle_event

    - name: Set SELinux boolean abrt_handle_event accordingly
      seboolean:
        name: abrt_handle_event
        state: '{{ var_abrt_handle_event }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_handle_event

#### Rule Disable the abrt_upload_watch_anon_write SELinux Boolean [ref]

By default, the SELinux boolean `abrt_upload_watch_anon_write` is enabled. This setting should be disabled as it allows the Automatic Bug Report Tool (ABRT) to modify public files used for public file transfer services. To disable the `abrt_upload_watch_anon_write` SELinux boolean, run the following command:

    $ sudo setsebool -P abrt_upload_watch_anon_write off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_abrt_upload_watch_anon_write
Identifiers and References | References: 3.7.2

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_abrt_upload_watch_anon_write='true'

    setsebool -P abrt_upload_watch_anon_write $var_abrt_upload_watch_anon_write

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_abrt_upload_watch_anon_write # promote to variable
      set_fact:
        var_abrt_upload_watch_anon_write: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_upload_watch_anon_write

    - name: Set SELinux boolean abrt_upload_watch_anon_write accordingly
      seboolean:
        name: abrt_upload_watch_anon_write
        state: '{{ var_abrt_upload_watch_anon_write }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.7.2
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_abrt_upload_watch_anon_write

#### Rule Enable the auditadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `auditadm_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `auditadm_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P auditadm_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_auditadm_exec_content
Identifiers and References | References: 80424-5, 0582, 0584, 05885, 0586, 0846, 0957

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_auditadm_exec_content='true'

    setsebool -P auditadm_exec_content $var_auditadm_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_auditadm_exec_content # promote to variable
      set_fact:
        var_auditadm_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-80424-5
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_auditadm_exec_content

    - name: Set SELinux boolean auditadm_exec_content accordingly
      seboolean:
        name: auditadm_exec_content
        state: '{{ var_auditadm_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-80424-5
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_auditadm_exec_content

#### Rule Disable the cron_can_relabel SELinux Boolean [ref]

By default, the SELinux boolean `cron_can_relabel` is disabled. If this setting is enabled, it should be disabled. To disable the `cron_can_relabel` SELinux boolean, run the following command:

    $ sudo setsebool -P cron_can_relabel off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_cron_can_relabel
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_cron_can_relabel='false'

    setsebool -P cron_can_relabel $var_cron_can_relabel

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_cron_can_relabel # promote to variable
      set_fact:
        var_cron_can_relabel: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_can_relabel

    - name: Set SELinux boolean cron_can_relabel accordingly
      seboolean:
        name: cron_can_relabel
        state: '{{ var_cron_can_relabel }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_can_relabel

#### Rule Disable the cron_system_cronjob_use_shares SELinux Boolean [ref]

By default, the SELinux boolean `cron_system_cronjob_use_shares` is disabled. If this setting is enabled, it should be disabled. To disable the `cron_system_cronjob_use_shares` SELinux boolean, run the following command:

    $ sudo setsebool -P cron_system_cronjob_use_shares off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_cron_system_cronjob_use_shares
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_cron_system_cronjob_use_shares='false'

    setsebool -P cron_system_cronjob_use_shares $var_cron_system_cronjob_use_shares

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_cron_system_cronjob_use_shares # promote to variable
      set_fact:
        var_cron_system_cronjob_use_shares: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_system_cronjob_use_shares

    - name: Set SELinux boolean cron_system_cronjob_use_shares accordingly
      seboolean:
        name: cron_system_cronjob_use_shares
        state: '{{ var_cron_system_cronjob_use_shares }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_system_cronjob_use_shares

#### Rule Enable the cron_userdomain_transition SELinux Boolean [ref]

By default, the SELinux boolean `cron_userdomain_transition` is enabled. This setting should be enabled as end user cron jobs run in their default associated user domain(s) instead of the general cronjob domain. To enable the `cron_userdomain_transition` SELinux boolean, run the following command:

    $ sudo setsebool -P cron_userdomain_transition on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_cron_userdomain_transition
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_cron_userdomain_transition='true'

    setsebool -P cron_userdomain_transition $var_cron_userdomain_transition

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_cron_userdomain_transition # promote to variable
      set_fact:
        var_cron_userdomain_transition: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_userdomain_transition

    - name: Set SELinux boolean cron_userdomain_transition accordingly
      seboolean:
        name: cron_userdomain_transition
        state: '{{ var_cron_userdomain_transition }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_cron_userdomain_transition

#### Rule Disable the daemons_dump_core SELinux Boolean [ref]

By default, the SELinux boolean `daemons_dump_core` is disabled. If this setting is enabled, it should be disabled. To disable the `daemons_dump_core` SELinux boolean, run the following command:

    $ sudo setsebool -P daemons_dump_core off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_daemons_dump_core
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_daemons_dump_core='false'

    setsebool -P daemons_dump_core $var_daemons_dump_core

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_daemons_dump_core # promote to variable
      set_fact:
        var_daemons_dump_core: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_dump_core

    - name: Set SELinux boolean daemons_dump_core accordingly
      seboolean:
        name: daemons_dump_core
        state: '{{ var_daemons_dump_core }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_dump_core

#### Rule Disable the daemons_use_tcp_wrapper SELinux Boolean [ref]

By default, the SELinux boolean `daemons_use_tcp_wrapper` is disabled. If this setting is enabled, it should be disabled. To disable the `daemons_use_tcp_wrapper` SELinux boolean, run the following command:

    $ sudo setsebool -P daemons_use_tcp_wrapper off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_daemons_use_tcp_wrapper
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_daemons_use_tcp_wrapper='false'

    setsebool -P daemons_use_tcp_wrapper $var_daemons_use_tcp_wrapper

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_daemons_use_tcp_wrapper # promote to variable
      set_fact:
        var_daemons_use_tcp_wrapper: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_use_tcp_wrapper

    - name: Set SELinux boolean daemons_use_tcp_wrapper accordingly
      seboolean:
        name: daemons_use_tcp_wrapper
        state: '{{ var_daemons_use_tcp_wrapper }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_use_tcp_wrapper

#### Rule Disable the daemons_use_tty SELinux Boolean [ref]

By default, the SELinux boolean `daemons_use_tty` is disabled. If this setting is enabled, it should be disabled. To disable the `daemons_use_tty` SELinux boolean, run the following command:

    $ sudo setsebool -P daemons_use_tty off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_daemons_use_tty
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_daemons_use_tty='false'

    setsebool -P daemons_use_tty $var_daemons_use_tty

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_daemons_use_tty # promote to variable
      set_fact:
        var_daemons_use_tty: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_use_tty

    - name: Set SELinux boolean daemons_use_tty accordingly
      seboolean:
        name: daemons_use_tty
        state: '{{ var_daemons_use_tty }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_daemons_use_tty

#### Rule Configure the deny_execmem SELinux Boolean [ref]

By default, the SELinux boolean `deny_execmem` is disabled. This setting should be configured to false.
To set the `deny_execmem` SELinux boolean, run the following command:

    $ sudo setsebool -P deny_execmem false

Warning: This rule doesn't come with a remediation, as enabling this SELinux boolean can cause applications to malfunction, for example Graphical login managers and Firefox.
Warning: Proper function and stability should be assessed before applying enabling the SELinux boolean in production systems.

Rationale: | Allowing user domain applications to map a memory region as both writable and executable makes them more susceptible to data execution attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_deny_execmem
Identifiers and References | References: BP28(R67)

#### Rule Disable the deny_ptrace SELinux Boolean [ref]

By default, the SELinux boolean `deny_ptrace` is disabled. If this setting is enabled, it should be disabled. To disable the `deny_ptrace` SELinux boolean, run the following command:

    $ sudo setsebool -P deny_ptrace off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_deny_ptrace
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_deny_ptrace='false'

    setsebool -P deny_ptrace $var_deny_ptrace

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_deny_ptrace # promote to variable
      set_fact:
        var_deny_ptrace: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_deny_ptrace

    - name: Set SELinux boolean deny_ptrace accordingly
      seboolean:
        name: deny_ptrace
        state: '{{ var_deny_ptrace }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_deny_ptrace

#### Rule Enable the domain_fd_use SELinux Boolean [ref]

By default, the SELinux boolean `domain_fd_use` is enabled. If this setting is disabled, it should be enabled. To enable the `domain_fd_use` SELinux boolean, run the following command:

    $ sudo setsebool -P domain_fd_use on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_domain_fd_use
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_domain_fd_use='true'

    setsebool -P domain_fd_use $var_domain_fd_use

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_domain_fd_use # promote to variable
      set_fact:
        var_domain_fd_use: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_domain_fd_use

    - name: Set SELinux boolean domain_fd_use accordingly
      seboolean:
        name: domain_fd_use
        state: '{{ var_domain_fd_use }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_domain_fd_use

#### Rule Disable the domain_kernel_load_modules SELinux Boolean [ref]

By default, the SELinux boolean `domain_kernel_load_modules` is disabled. If this setting is enabled, it should be disabled. To disable the `domain_kernel_load_modules` SELinux boolean, run the following command:

    $ sudo setsebool -P domain_kernel_load_modules off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_domain_kernel_load_modules
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_domain_kernel_load_modules='false'

    setsebool -P domain_kernel_load_modules $var_domain_kernel_load_modules

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_domain_kernel_load_modules # promote to variable
      set_fact:
        var_domain_kernel_load_modules: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_domain_kernel_load_modules

    - name: Set SELinux boolean domain_kernel_load_modules accordingly
      seboolean:
        name: domain_kernel_load_modules
        state: '{{ var_domain_kernel_load_modules }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_domain_kernel_load_modules

#### Rule Enable the fips_mode SELinux Boolean [ref]

By default, the SELinux boolean `fips_mode` is enabled. This allows all SELinux domains to execute in `fips_mode`. If this setting is disabled, it should be enabled. To enable the `fips_mode` SELinux boolean, run the following command:

    $ sudo setsebool -P fips_mode on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_fips_mode
Identifiers and References | References: 13, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.13.11, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, SC-12(2), SC-12(3), IA-7, SC-13, CM-6(a), SC-12, PR.DS-5

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_fips_mode='true'

    setsebool -P fips_mode $var_fips_mode

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_fips_mode # promote to variable
      set_fact:
        var_fips_mode: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_fips_mode

    - name: Set SELinux boolean fips_mode accordingly
      seboolean:
        name: fips_mode
        state: '{{ var_fips_mode }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.13.11
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-7
      - NIST-800-53-SC-12
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_fips_mode

#### Rule Disable the gpg_web_anon_write SELinux Boolean [ref]

By default, the SELinux boolean `gpg_web_anon_write` is disabled. If this setting is enabled, it should be disabled. To disable the `gpg_web_anon_write` SELinux boolean, run the following command:

    $ sudo setsebool -P gpg_web_anon_write off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_gpg_web_anon_write
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_gpg_web_anon_write='false'

    setsebool -P gpg_web_anon_write $var_gpg_web_anon_write

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_gpg_web_anon_write # promote to variable
      set_fact:
        var_gpg_web_anon_write: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_gpg_web_anon_write

    - name: Set SELinux boolean gpg_web_anon_write accordingly
      seboolean:
        name: gpg_web_anon_write
        state: '{{ var_gpg_web_anon_write }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_gpg_web_anon_write

#### Rule Disable the guest_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `guest_exec_content` is enabled. This setting should be disabled as no guest accounts should be used. To disable the `guest_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P guest_exec_content off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_guest_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_guest_exec_content='true'

    setsebool -P guest_exec_content $var_guest_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_guest_exec_content # promote to variable
      set_fact:
        var_guest_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_guest_exec_content

    - name: Set SELinux boolean guest_exec_content accordingly
      seboolean:
        name: guest_exec_content
        state: '{{ var_guest_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_guest_exec_content

#### Rule Enable the kerberos_enabled SELinux Boolean [ref]

By default, the SELinux boolean `kerberos_enabled` is enabled. If this setting is disabled, it should be enabled to allow confined applications to run with Kerberos. To enable the `kerberos_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P kerberos_enabled on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_kerberos_enabled
Identifiers and References | References: 0418, 1055, 1402

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_kerberos_enabled='true'

    setsebool -P kerberos_enabled $var_kerberos_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_kerberos_enabled # promote to variable
      set_fact:
        var_kerberos_enabled: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_kerberos_enabled

    - name: Set SELinux boolean kerberos_enabled accordingly
      seboolean:
        name: kerberos_enabled
        state: '{{ var_kerberos_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_kerberos_enabled

#### Rule Enable the logadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `logadm_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `logadm_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P logadm_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_logadm_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_logadm_exec_content='true'

    setsebool -P logadm_exec_content $var_logadm_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_logadm_exec_content # promote to variable
      set_fact:
        var_logadm_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logadm_exec_content

    - name: Set SELinux boolean logadm_exec_content accordingly
      seboolean:
        name: logadm_exec_content
        state: '{{ var_logadm_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logadm_exec_content

#### Rule Disable the logging_syslogd_can_sendmail SELinux Boolean [ref]

By default, the SELinux boolean `logging_syslogd_can_sendmail` is disabled. If this setting is enabled, it should be disabled. To disable the `logging_syslogd_can_sendmail` SELinux boolean, run the following command:

    $ sudo setsebool -P logging_syslogd_can_sendmail off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_logging_syslogd_can_sendmail
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_logging_syslogd_can_sendmail='false'

    setsebool -P logging_syslogd_can_sendmail $var_logging_syslogd_can_sendmail

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_logging_syslogd_can_sendmail # promote to variable
      set_fact:
        var_logging_syslogd_can_sendmail: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logging_syslogd_can_sendmail

    - name: Set SELinux boolean logging_syslogd_can_sendmail accordingly
      seboolean:
        name: logging_syslogd_can_sendmail
        state: '{{ var_logging_syslogd_can_sendmail }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logging_syslogd_can_sendmail

#### Rule Enable the logging_syslogd_use_tty SELinux Boolean [ref]

By default, the SELinux boolean `logging_syslogd_use_tty` is enabled. If this setting is disabled, it should be enabled as it allows `syslog` the ability to read/write to terminal. To enable the `logging_syslogd_use_tty` SELinux boolean, run the following command:

    $ sudo setsebool -P logging_syslogd_use_tty on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_logging_syslogd_use_tty
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_logging_syslogd_use_tty='true'

    setsebool -P logging_syslogd_use_tty $var_logging_syslogd_use_tty

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_logging_syslogd_use_tty # promote to variable
      set_fact:
        var_logging_syslogd_use_tty: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logging_syslogd_use_tty

    - name: Set SELinux boolean logging_syslogd_use_tty accordingly
      seboolean:
        name: logging_syslogd_use_tty
        state: '{{ var_logging_syslogd_use_tty }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_logging_syslogd_use_tty

#### Rule Enable the login_console_enabled SELinux Boolean [ref]

By default, the SELinux boolean `login_console_enabled` is enabled. If this setting is disabled, it should be enabled as it allows login from `/dev/console` to a console session. To enable the `login_console_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P login_console_enabled on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_login_console_enabled
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_login_console_enabled='true'

    setsebool -P login_console_enabled $var_login_console_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_login_console_enabled # promote to variable
      set_fact:
        var_login_console_enabled: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_login_console_enabled

    - name: Set SELinux boolean login_console_enabled accordingly
      seboolean:
        name: login_console_enabled
        state: '{{ var_login_console_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_login_console_enabled

#### Rule Disable the mmap_low_allowed SELinux Boolean [ref]

By default, the SELinux boolean `mmap_low_allowed` is disabled. If this setting is enabled, it should be disabled. To disable the `mmap_low_allowed` SELinux boolean, run the following command:

    $ sudo setsebool -P mmap_low_allowed off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_mmap_low_allowed
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_mmap_low_allowed='false'

    setsebool -P mmap_low_allowed $var_mmap_low_allowed

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_mmap_low_allowed # promote to variable
      set_fact:
        var_mmap_low_allowed: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mmap_low_allowed

    - name: Set SELinux boolean mmap_low_allowed accordingly
      seboolean:
        name: mmap_low_allowed
        state: '{{ var_mmap_low_allowed }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mmap_low_allowed

#### Rule Disable the mock_enable_homedirs SELinux Boolean [ref]

By default, the SELinux boolean `mock_enable_homedirs` is disabled. If this setting is enabled, it should be disabled. To disable the `mock_enable_homedirs` SELinux boolean, run the following command:

    $ sudo setsebool -P mock_enable_homedirs off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_mock_enable_homedirs
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_mock_enable_homedirs='false'

    setsebool -P mock_enable_homedirs $var_mock_enable_homedirs

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_mock_enable_homedirs # promote to variable
      set_fact:
        var_mock_enable_homedirs: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mock_enable_homedirs

    - name: Set SELinux boolean mock_enable_homedirs accordingly
      seboolean:
        name: mock_enable_homedirs
        state: '{{ var_mock_enable_homedirs }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mock_enable_homedirs

#### Rule Enable the mount_anyfile SELinux Boolean [ref]

By default, the SELinux boolean `mount_anyfile` is enabled. If this setting is disabled, it should be enabled to allow any file or directory to be mounted. To enable the `mount_anyfile` SELinux boolean, run the following command:

    $ sudo setsebool -P mount_anyfile on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_mount_anyfile
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_mount_anyfile='true'

    setsebool -P mount_anyfile $var_mount_anyfile

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_mount_anyfile # promote to variable
      set_fact:
        var_mount_anyfile: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mount_anyfile

    - name: Set SELinux boolean mount_anyfile accordingly
      seboolean:
        name: mount_anyfile
        state: '{{ var_mount_anyfile }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_mount_anyfile

#### Rule Configure the polyinstantiation_enabled SELinux Boolean [ref]

By default, the SELinux boolean `polyinstantiation_enabled` is disabled. This setting should be configured to false.
To set the `polyinstantiation_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P polyinstantiation_enabled false

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_polyinstantiation_enabled
Identifiers and References | References: BP28(R39)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_polyinstantiation_enabled='false'

    setsebool -P polyinstantiation_enabled $var_polyinstantiation_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_polyinstantiation_enabled # promote to variable
      set_fact:
        var_polyinstantiation_enabled: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_polyinstantiation_enabled

    - name: Set SELinux boolean polyinstantiation_enabled accordingly
      seboolean:
        name: polyinstantiation_enabled
        state: '{{ var_polyinstantiation_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_polyinstantiation_enabled

#### Rule Enable the secadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `secadm_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `secadm_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P secadm_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_secadm_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_secadm_exec_content='true'

    setsebool -P secadm_exec_content $var_secadm_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_secadm_exec_content # promote to variable
      set_fact:
        var_secadm_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secadm_exec_content

    - name: Set SELinux boolean secadm_exec_content accordingly
      seboolean:
        name: secadm_exec_content
        state: '{{ var_secadm_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secadm_exec_content

#### Rule Disable the secure_mode SELinux Boolean [ref]

By default, the SELinux boolean `secure_mode` is disabled. If this setting is enabled, it should be disabled. To disable the `secure_mode` SELinux boolean, run the following command:

    $ sudo setsebool -P secure_mode off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_secure_mode
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_secure_mode='false'

    setsebool -P secure_mode $var_secure_mode

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_secure_mode # promote to variable
      set_fact:
        var_secure_mode: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode

    - name: Set SELinux boolean secure_mode accordingly
      seboolean:
        name: secure_mode
        state: '{{ var_secure_mode }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode

#### Rule Configure the secure_mode_insmod SELinux Boolean [ref]

By default, the SELinux boolean `secure_mode_insmod` is disabled. This setting should be configured to false.
To set the `secure_mode_insmod` SELinux boolean, run the following command:

    $ sudo setsebool -P secure_mode_insmod false

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_secure_mode_insmod
Identifiers and References | References: BP28(R67)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_secure_mode_insmod='false'

    setsebool -P secure_mode_insmod $var_secure_mode_insmod

    # Preload vfat in initramfs, otherwise the system fails to reboot
    echo "vfat" >> /etc/modules-load.d/vfat.conf
    dracut -f --regenerate-all

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_secure_mode_insmod # promote to variable
      set_fact:
        var_secure_mode_insmod: !!str false
      tags:
        - always

    - name: Configure the secure_mode_insmod SELinux Boolean - Ensure libsemanage-python
        installed
      ansible.builtin.package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_insmod

    - name: Configure the secure_mode_insmod SELinux Boolean - Set SELinux boolean secure_mode_insmod
        accordingly
      ansible.posix.seboolean:
        name: secure_mode_insmod
        state: '{{ var_secure_mode_insmod }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_insmod

    - name: Configure the secure_mode_insmod SELinux Boolean - Add vfat to static kernel
        module list
      ansible.builtin.lineinfile:
        create: true
        dest: /etc/modules-load.d/vfat.conf
        regexp: ^\s*\bvfat\b
        line: vfat
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_insmod

    - name: Configure the secure_mode_insmod SELinux Boolean - Regenerate initramfs
      ansible.builtin.command:
        cmd: dracut -f --regenerate-all
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_insmod

#### Rule Disable the secure_mode_policyload SELinux Boolean [ref]

By default, the SELinux boolean `secure_mode_policyload` is disabled. If this setting is enabled, it should be disabled. To disable the `secure_mode_policyload` SELinux boolean, run the following command:

    $ sudo setsebool -P secure_mode_policyload off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_secure_mode_policyload
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_secure_mode_policyload='false'

    setsebool -P secure_mode_policyload $var_secure_mode_policyload

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_secure_mode_policyload # promote to variable
      set_fact:
        var_secure_mode_policyload: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_policyload

    - name: Set SELinux boolean secure_mode_policyload accordingly
      seboolean:
        name: secure_mode_policyload
        state: '{{ var_secure_mode_policyload }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_secure_mode_policyload

#### Rule Configure the selinuxuser_direct_dri_enabled SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_direct_dri_enabled` is enabled. If XWindows is not installed or used on the system, this setting should be disabled. Otherwise, enable it. To disable the `selinuxuser_direct_dri_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_direct_dri_enabled off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_direct_dri_enabled
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_direct_dri_enabled='true'

    setsebool -P selinuxuser_direct_dri_enabled $var_selinuxuser_direct_dri_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_direct_dri_enabled # promote to variable
      set_fact:
        var_selinuxuser_direct_dri_enabled: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_direct_dri_enabled

    - name: Set SELinux boolean selinuxuser_direct_dri_enabled accordingly
      seboolean:
        name: selinuxuser_direct_dri_enabled
        state: '{{ var_selinuxuser_direct_dri_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_direct_dri_enabled

#### Rule Disable the selinuxuser_execheap SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_execheap` is disabled. When enabled this boolean is enabled it allows selinuxusers to execute code from the heap. If this setting is enabled, it should be disabled. To disable the `selinuxuser_execheap` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_execheap off

Rationale: | Disabling code execution from the heap blocks buffer overflow attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execheap
Identifiers and References | References: BP28(R67), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_execheap='false'

    setsebool -P selinuxuser_execheap $var_selinuxuser_execheap

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_execheap # promote to variable
      set_fact:
        var_selinuxuser_execheap: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execheap

    - name: Set SELinux boolean selinuxuser_execheap accordingly
      seboolean:
        name: selinuxuser_execheap
        state: '{{ var_selinuxuser_execheap }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execheap

#### Rule Enable the selinuxuser_execmod SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_execmod` is enabled. If this setting is disabled, it should be enabled. To enable the `selinuxuser_execmod` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_execmod on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execmod
Identifiers and References | References: 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_execmod='true'

    setsebool -P selinuxuser_execmod $var_selinuxuser_execmod

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_execmod # promote to variable
      set_fact:
        var_selinuxuser_execmod: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execmod

    - name: Set SELinux boolean selinuxuser_execmod accordingly
      seboolean:
        name: selinuxuser_execmod
        state: '{{ var_selinuxuser_execmod }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execmod

#### Rule Disable the selinuxuser_execstack SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_execstack` is enabled. This setting should be disabled as unconfined executables should not be able to make their stack executable. To disable the `selinuxuser_execstack` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_execstack off

Rationale: | Disabling code execution from the stack blocks buffer overflow attacks.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_execstack
Identifiers and References | References: BP28(R67), 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_execstack='false'

    setsebool -P selinuxuser_execstack $var_selinuxuser_execstack

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_execstack # promote to variable
      set_fact:
        var_selinuxuser_execstack: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execstack

    - name: Set SELinux boolean selinuxuser_execstack accordingly
      seboolean:
        name: selinuxuser_execstack
        state: '{{ var_selinuxuser_execstack }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_execstack

#### Rule Disable the selinuxuser_mysql_connect_enabled SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_mysql_connect_enabled` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_mysql_connect_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_mysql_connect_enabled off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_mysql_connect_enabled
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_mysql_connect_enabled='false'

    setsebool -P selinuxuser_mysql_connect_enabled $var_selinuxuser_mysql_connect_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_mysql_connect_enabled # promote to variable
      set_fact:
        var_selinuxuser_mysql_connect_enabled: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_mysql_connect_enabled

    - name: Set SELinux boolean selinuxuser_mysql_connect_enabled accordingly
      seboolean:
        name: selinuxuser_mysql_connect_enabled
        state: '{{ var_selinuxuser_mysql_connect_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_mysql_connect_enabled

#### Rule Enable the selinuxuser_ping SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_ping` is enabled. If this setting is disabled, it should be enabled as it allows confined users to use ping and traceroute which is helpful for network troubleshooting. To enable the `selinuxuser_ping` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_ping on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_ping
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_ping='true'

    setsebool -P selinuxuser_ping $var_selinuxuser_ping

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_ping # promote to variable
      set_fact:
        var_selinuxuser_ping: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_ping

    - name: Set SELinux boolean selinuxuser_ping accordingly
      seboolean:
        name: selinuxuser_ping
        state: '{{ var_selinuxuser_ping }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_ping

#### Rule Disable the selinuxuser_postgresql_connect_enabled SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_postgresql_connect_enabled` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_postgresql_connect_enabled` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_postgresql_connect_enabled off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_postgresql_connect_enabled
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_postgresql_connect_enabled='false'

    setsebool -P selinuxuser_postgresql_connect_enabled $var_selinuxuser_postgresql_connect_enabled

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_postgresql_connect_enabled # promote to variable
      set_fact:
        var_selinuxuser_postgresql_connect_enabled: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_postgresql_connect_enabled

    - name: Set SELinux boolean selinuxuser_postgresql_connect_enabled accordingly
      seboolean:
        name: selinuxuser_postgresql_connect_enabled
        state: '{{ var_selinuxuser_postgresql_connect_enabled }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_postgresql_connect_enabled

#### Rule Disable the selinuxuser_rw_noexattrfile SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_rw_noexattrfile` is enabled. This setting should be disabled as users should not be able to read/write files on filesystems that do not have extended attributes e.g. FAT, CDROM, FLOPPY, etc. To disable the `selinuxuser_rw_noexattrfile` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_rw_noexattrfile off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_rw_noexattrfile
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_rw_noexattrfile='true'

    setsebool -P selinuxuser_rw_noexattrfile $var_selinuxuser_rw_noexattrfile

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_rw_noexattrfile # promote to variable
      set_fact:
        var_selinuxuser_rw_noexattrfile: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_rw_noexattrfile

    - name: Set SELinux boolean selinuxuser_rw_noexattrfile accordingly
      seboolean:
        name: selinuxuser_rw_noexattrfile
        state: '{{ var_selinuxuser_rw_noexattrfile }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_rw_noexattrfile

#### Rule Disable the selinuxuser_share_music SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_share_music` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_share_music` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_share_music off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_share_music
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_share_music='false'

    setsebool -P selinuxuser_share_music $var_selinuxuser_share_music

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_share_music # promote to variable
      set_fact:
        var_selinuxuser_share_music: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_share_music

    - name: Set SELinux boolean selinuxuser_share_music accordingly
      seboolean:
        name: selinuxuser_share_music
        state: '{{ var_selinuxuser_share_music }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_share_music

#### Rule Disable the selinuxuser_tcp_server SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_tcp_server` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_tcp_server` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_tcp_server off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_tcp_server
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_tcp_server='false'

    setsebool -P selinuxuser_tcp_server $var_selinuxuser_tcp_server

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_tcp_server # promote to variable
      set_fact:
        var_selinuxuser_tcp_server: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_tcp_server

    - name: Set SELinux boolean selinuxuser_tcp_server accordingly
      seboolean:
        name: selinuxuser_tcp_server
        state: '{{ var_selinuxuser_tcp_server }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_tcp_server

#### Rule Disable the selinuxuser_udp_server SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_udp_server` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_udp_server` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_udp_server off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_udp_server
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_udp_server='false'

    setsebool -P selinuxuser_udp_server $var_selinuxuser_udp_server

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_udp_server # promote to variable
      set_fact:
        var_selinuxuser_udp_server: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_udp_server

    - name: Set SELinux boolean selinuxuser_udp_server accordingly
      seboolean:
        name: selinuxuser_udp_server
        state: '{{ var_selinuxuser_udp_server }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_udp_server

#### Rule Disable the selinuxuser_use_ssh_chroot SELinux Boolean [ref]

By default, the SELinux boolean `selinuxuser_use_ssh_chroot` is disabled. If this setting is enabled, it should be disabled. To disable the `selinuxuser_use_ssh_chroot` SELinux boolean, run the following command:

    $ sudo setsebool -P selinuxuser_use_ssh_chroot off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_selinuxuser_use_ssh_chroot
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinuxuser_use_ssh_chroot='false'

    setsebool -P selinuxuser_use_ssh_chroot $var_selinuxuser_use_ssh_chroot

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_selinuxuser_use_ssh_chroot # promote to variable
      set_fact:
        var_selinuxuser_use_ssh_chroot: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_use_ssh_chroot

    - name: Set SELinux boolean selinuxuser_use_ssh_chroot accordingly
      seboolean:
        name: selinuxuser_use_ssh_chroot
        state: '{{ var_selinuxuser_use_ssh_chroot }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_selinuxuser_use_ssh_chroot

#### Rule Disable the ssh_chroot_rw_homedirs SELinux Boolean [ref]

By default, the SELinux boolean `ssh_chroot_rw_homedirs` is disabled. If this setting is enabled, it should be disabled. To disable the `ssh_chroot_rw_homedirs` SELinux boolean, run the following command:

    $ sudo setsebool -P ssh_chroot_rw_homedirs off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_ssh_chroot_rw_homedirs
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_ssh_chroot_rw_homedirs='false'

    setsebool -P ssh_chroot_rw_homedirs $var_ssh_chroot_rw_homedirs

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_ssh_chroot_rw_homedirs # promote to variable
      set_fact:
        var_ssh_chroot_rw_homedirs: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_chroot_rw_homedirs

    - name: Set SELinux boolean ssh_chroot_rw_homedirs accordingly
      seboolean:
        name: ssh_chroot_rw_homedirs
        state: '{{ var_ssh_chroot_rw_homedirs }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_chroot_rw_homedirs

#### Rule Disable the ssh_keysign SELinux Boolean [ref]

By default, the SELinux boolean `ssh_keysign` is disabled. If this setting is enabled, it should be disabled. To disable the `ssh_keysign` SELinux boolean, run the following command:

    $ sudo setsebool -P ssh_keysign off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_ssh_keysign
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_ssh_keysign='false'

    setsebool -P ssh_keysign $var_ssh_keysign

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_ssh_keysign # promote to variable
      set_fact:
        var_ssh_keysign: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_keysign

    - name: Set SELinux boolean ssh_keysign accordingly
      seboolean:
        name: ssh_keysign
        state: '{{ var_ssh_keysign }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_keysign

#### Rule Disable the ssh_sysadm_login SELinux Boolean [ref]

By default, the SELinux boolean `ssh_sysadm_login` is disabled. If this setting is enabled, it should be disabled. To disable the `ssh_sysadm_login` SELinux boolean, run the following command:

    $ sudo setsebool -P ssh_sysadm_login off

Rationale:

Preventing non-privileged users from executing privileged functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, establishing accounts, performing system integrity checks, or administering cryptographic key management activities. Non-privileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from non-privileged users.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_ssh_sysadm_login
Identifiers and References | References: BP28(R67), CCI-002165, CCI-002235, SRG-OS-000324-GPOS-00125, OL07-00-020022, SV-250310r877392_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_ssh_sysadm_login='false'

    setsebool -P ssh_sysadm_login $var_ssh_sysadm_login

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_ssh_sysadm_login # promote to variable
      set_fact:
        var_ssh_sysadm_login: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020022
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_sysadm_login

    - name: Set SELinux boolean ssh_sysadm_login accordingly
      seboolean:
        name: ssh_sysadm_login
        state: '{{ var_ssh_sysadm_login }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020022
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_ssh_sysadm_login

#### Rule Enable the staff_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `staff_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `staff_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P staff_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_staff_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_staff_exec_content='true'

    setsebool -P staff_exec_content $var_staff_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_staff_exec_content # promote to variable
      set_fact:
        var_staff_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_staff_exec_content

    - name: Set SELinux boolean staff_exec_content accordingly
      seboolean:
        name: staff_exec_content
        state: '{{ var_staff_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_staff_exec_content

#### Rule Enable the sysadm_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `sysadm_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `sysadm_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P sysadm_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_sysadm_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_sysadm_exec_content='true'

    setsebool -P sysadm_exec_content $var_sysadm_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_sysadm_exec_content # promote to variable
      set_fact:
        var_sysadm_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_sysadm_exec_content

    - name: Set SELinux boolean sysadm_exec_content accordingly
      seboolean:
        name: sysadm_exec_content
        state: '{{ var_sysadm_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_sysadm_exec_content

#### Rule Enable the unconfined_login SELinux Boolean [ref]

By default, the SELinux boolean `unconfined_login` is enabled. If this setting is disabled, it should be enabled. To enable the `unconfined_login` SELinux boolean, run the following command:

    $ sudo setsebool -P unconfined_login on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_unconfined_login
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_unconfined_login='true'

    setsebool -P unconfined_login $var_unconfined_login

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_unconfined_login # promote to variable
      set_fact:
        var_unconfined_login: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_unconfined_login

    - name: Set SELinux boolean unconfined_login accordingly
      seboolean:
        name: unconfined_login
        state: '{{ var_unconfined_login }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_unconfined_login

#### Rule Disable the use_ecryptfs_home_dirs SELinux Boolean [ref]

By default, the SELinux boolean `use_ecryptfs_home_dirs` is disabled. If this setting is enabled, it should be disabled. To disable the `use_ecryptfs_home_dirs` SELinux boolean, run the following command:

    $ sudo setsebool -P use_ecryptfs_home_dirs off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_use_ecryptfs_home_dirs
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_use_ecryptfs_home_dirs='false'

    setsebool -P use_ecryptfs_home_dirs $var_use_ecryptfs_home_dirs

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_use_ecryptfs_home_dirs # promote to variable
      set_fact:
        var_use_ecryptfs_home_dirs: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_use_ecryptfs_home_dirs

    - name: Set SELinux boolean use_ecryptfs_home_dirs accordingly
      seboolean:
        name: use_ecryptfs_home_dirs
        state: '{{ var_use_ecryptfs_home_dirs }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_use_ecryptfs_home_dirs

#### Rule Enable the user_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `user_exec_content` is enabled. If this setting is disabled, it should be enabled. To enable the `user_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P user_exec_content on

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_user_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_user_exec_content='true'

    setsebool -P user_exec_content $var_user_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_user_exec_content # promote to variable
      set_fact:
        var_user_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_user_exec_content

    - name: Set SELinux boolean user_exec_content accordingly
      seboolean:
        name: user_exec_content
        state: '{{ var_user_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_user_exec_content

#### Rule Disable the xdm_bind_vnc_tcp_port SELinux Boolean [ref]

By default, the SELinux boolean `xdm_bind_vnc_tcp_port` is disabled. If this setting is enabled, it should be disabled. To disable the `xdm_bind_vnc_tcp_port` SELinux boolean, run the following command:

    $ sudo setsebool -P xdm_bind_vnc_tcp_port off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xdm_bind_vnc_tcp_port
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xdm_bind_vnc_tcp_port='false'

    setsebool -P xdm_bind_vnc_tcp_port $var_xdm_bind_vnc_tcp_port

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xdm_bind_vnc_tcp_port # promote to variable
      set_fact:
        var_xdm_bind_vnc_tcp_port: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_bind_vnc_tcp_port

    - name: Set SELinux boolean xdm_bind_vnc_tcp_port accordingly
      seboolean:
        name: xdm_bind_vnc_tcp_port
        state: '{{ var_xdm_bind_vnc_tcp_port }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_bind_vnc_tcp_port

#### Rule Disable the xdm_exec_bootloader SELinux Boolean [ref]

By default, the SELinux boolean `xdm_exec_bootloader` is disabled. If this setting is enabled, it should be disabled. To disable the `xdm_exec_bootloader` SELinux boolean, run the following command:

    $ sudo setsebool -P xdm_exec_bootloader off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xdm_exec_bootloader
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xdm_exec_bootloader='false'

    setsebool -P xdm_exec_bootloader $var_xdm_exec_bootloader

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xdm_exec_bootloader # promote to variable
      set_fact:
        var_xdm_exec_bootloader: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_exec_bootloader

    - name: Set SELinux boolean xdm_exec_bootloader accordingly
      seboolean:
        name: xdm_exec_bootloader
        state: '{{ var_xdm_exec_bootloader }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_exec_bootloader

#### Rule Disable the xdm_sysadm_login SELinux Boolean [ref]

By default, the SELinux boolean `xdm_sysadm_login` is disabled. If this setting is enabled, it should be disabled. To disable the `xdm_sysadm_login` SELinux boolean, run the following command:

    $ sudo setsebool -P xdm_sysadm_login off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xdm_sysadm_login
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xdm_sysadm_login='false'

    setsebool -P xdm_sysadm_login $var_xdm_sysadm_login

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xdm_sysadm_login # promote to variable
      set_fact:
        var_xdm_sysadm_login: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_sysadm_login

    - name: Set SELinux boolean xdm_sysadm_login accordingly
      seboolean:
        name: xdm_sysadm_login
        state: '{{ var_xdm_sysadm_login }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_sysadm_login

#### Rule Disable the xdm_write_home SELinux Boolean [ref]

By default, the SELinux boolean `xdm_write_home` is disabled. If this setting is enabled, it should be disabled. To disable the `xdm_write_home` SELinux boolean, run the following command:

    $ sudo setsebool -P xdm_write_home off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xdm_write_home
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xdm_write_home='false'

    setsebool -P xdm_write_home $var_xdm_write_home

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xdm_write_home # promote to variable
      set_fact:
        var_xdm_write_home: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_write_home

    - name: Set SELinux boolean xdm_write_home accordingly
      seboolean:
        name: xdm_write_home
        state: '{{ var_xdm_write_home }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xdm_write_home

#### Rule Disable the xguest_connect_network SELinux Boolean [ref]

By default, the SELinux boolean `xguest_connect_network` is enabled. This setting should be disabled as guest users should not be able to configure `NetworkManager`. To disable the `xguest_connect_network` SELinux boolean, run the following command:

    $ sudo setsebool -P xguest_connect_network off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xguest_connect_network
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xguest_connect_network='true'

    setsebool -P xguest_connect_network $var_xguest_connect_network

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xguest_connect_network # promote to variable
      set_fact:
        var_xguest_connect_network: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_connect_network

    - name: Set SELinux boolean xguest_connect_network accordingly
      seboolean:
        name: xguest_connect_network
        state: '{{ var_xguest_connect_network }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_connect_network

#### Rule Disable the xguest_exec_content SELinux Boolean [ref]

By default, the SELinux boolean `xguest_exec_content` is enabled. This setting should be disabled as guest users should not be able to run executables. To disable the `xguest_exec_content` SELinux boolean, run the following command:

    $ sudo setsebool -P xguest_exec_content off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xguest_exec_content
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xguest_exec_content='true'

    setsebool -P xguest_exec_content $var_xguest_exec_content

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xguest_exec_content # promote to variable
      set_fact:
        var_xguest_exec_content: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_exec_content

    - name: Set SELinux boolean xguest_exec_content accordingly
      seboolean:
        name: xguest_exec_content
        state: '{{ var_xguest_exec_content }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_exec_content

#### Rule Disable the xguest_mount_media SELinux Boolean [ref]

By default, the SELinux boolean `xguest_mount_media` is enabled. This setting should be disabled as guest users should not be able to mount any media. To disable the `xguest_mount_media` SELinux boolean, run the following command:

    $ sudo setsebool -P xguest_mount_media off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xguest_mount_media
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xguest_mount_media='true'

    setsebool -P xguest_mount_media $var_xguest_mount_media

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xguest_mount_media # promote to variable
      set_fact:
        var_xguest_mount_media: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_mount_media

    - name: Set SELinux boolean xguest_mount_media accordingly
      seboolean:
        name: xguest_mount_media
        state: '{{ var_xguest_mount_media }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_mount_media

#### Rule Disable the xguest_use_bluetooth SELinux Boolean [ref]

By default, the SELinux boolean `xguest_use_bluetooth` is enabled. This setting should be disabled as guests users should not be able to access or use bluetooth. To disable the `xguest_use_bluetooth` SELinux boolean, run the following command:

    $ sudo setsebool -P xguest_use_bluetooth off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xguest_use_bluetooth
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xguest_use_bluetooth='true'

    setsebool -P xguest_use_bluetooth $var_xguest_use_bluetooth

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xguest_use_bluetooth # promote to variable
      set_fact:
        var_xguest_use_bluetooth: !!str true
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_use_bluetooth

    - name: Set SELinux boolean xguest_use_bluetooth accordingly
      seboolean:
        name: xguest_use_bluetooth
        state: '{{ var_xguest_use_bluetooth }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xguest_use_bluetooth

#### Rule Disable the xserver_clients_write_xshm SELinux Boolean [ref]

By default, the SELinux boolean `xserver_clients_write_xshm` is disabled. If this setting is enabled, it should be disabled. To disable the `xserver_clients_write_xshm` SELinux boolean, run the following command:

    $ sudo setsebool -P xserver_clients_write_xshm off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xserver_clients_write_xshm
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xserver_clients_write_xshm='false'

    setsebool -P xserver_clients_write_xshm $var_xserver_clients_write_xshm

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xserver_clients_write_xshm # promote to variable
      set_fact:
        var_xserver_clients_write_xshm: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_clients_write_xshm

    - name: Set SELinux boolean xserver_clients_write_xshm accordingly
      seboolean:
        name: xserver_clients_write_xshm
        state: '{{ var_xserver_clients_write_xshm }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_clients_write_xshm

#### Rule Disable the xserver_execmem SELinux Boolean [ref]

By default, the SELinux boolean `xserver_execmem` is disabled. If this setting is enabled, it should be disabled. To disable the `xserver_execmem` SELinux boolean, run the following command:

    $ sudo setsebool -P xserver_execmem off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xserver_execmem
Identifiers and References | References: BP28(R67)

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xserver_execmem='false'

    setsebool -P xserver_execmem $var_xserver_execmem

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xserver_execmem # promote to variable
      set_fact:
        var_xserver_execmem: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_execmem

    - name: Set SELinux boolean xserver_execmem accordingly
      seboolean:
        name: xserver_execmem
        state: '{{ var_xserver_execmem }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_execmem

#### Rule Disable the xserver_object_manager SELinux Boolean [ref]

By default, the SELinux boolean `xserver_object_manager` is disabled. If this setting is enabled, it should be disabled. To disable the `xserver_object_manager` SELinux boolean, run the following command:

    $ sudo setsebool -P xserver_object_manager off

Rationale: |
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sebool_xserver_object_manager
Identifiers and References |

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if ( ! ( [ "${container:-}" == "bwrap-osbuild" ] ) ) && [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_xserver_object_manager='false'

    setsebool -P xserver_object_manager $var_xserver_object_manager

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: XCCDF Value var_xserver_object_manager # promote to variable
      set_fact:
        var_xserver_object_manager: !!str false
      tags:
        - always

    - name: Ensure libsemanage-python installed
      package:
        name: libsemanage-python
        state: present
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_object_manager

    - name: Set SELinux boolean xserver_object_manager accordingly
      seboolean:
        name: xserver_object_manager
        state: '{{ var_xserver_object_manager }}'
        persistent: true
      when:
      - ( not ( lookup("env", "container") == "bwrap-osbuild" ) )
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - sebool_xserver_object_manager

#### Rule Ensure SELinux Not Disabled in /etc/default/grub [ref]

SELinux can be disabled at boot time by an argument in `/etc/default/grub`. Remove any instances of `selinux=0` from the kernel arguments in that file to prevent SELinux from being disabled at boot.
Rationale: | Disabling a major host protection feature, such as SELinux, at boot time prevents it from confining system services at boot time. Further, it increases the chances that it will remain off during system operation.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_grub2_enable_selinux

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-000022, CCI-000032, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-3(3)(a), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, 1.2.6

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { rpm --quiet -q grub2-common; }; then

    sed -i --follow-symlinks "s/selinux=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*
    sed -i --follow-symlinks "s/enforcing=0//gI" /etc/default/grub /etc/grub2.cfg /etc/grub.d/*

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Find /etc/grub.d/ files
      ansible.builtin.find:
        paths:
        - /etc/grub.d/
        follow: true
      register: result_grub_d
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
        in /etc/grub.d/ files
      ansible.builtin.replace:
        dest: '{{ item.path }}'
        regexp: (selinux|enforcing)=0
      with_items:
      - '{{ result_grub_d.files }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/grub2.cfg
        exists
      ansible.builtin.stat:
        path: /etc/grub2.cfg
      register: result_grub2_cfg_present
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Check if /etc/default/grub
        exists
      ansible.builtin.stat:
        path: /etc/default/grub
      register: result_default_grub_present
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
        in /etc/grub2.cfg
      ansible.builtin.replace:
        dest: /etc/grub2.cfg
        regexp: (selinux|enforcing)=0
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - result_grub2_cfg_present.stat.exists
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

    - name: Ensure SELinux Not Disabled in /etc/default/grub - Ensure SELinux Not Disabled
        in /etc/default/grub
      ansible.builtin.replace:
        dest: /etc/default/grub
        regexp: (selinux|enforcing)=0
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '"grub2-common" in ansible_facts.packages'
      - result_default_grub_present.stat.exists
      tags:
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - PCI-DSSv4-1.2.6
      - grub2_enable_selinux
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Ensure No Device Files are Unlabeled by SELinux [ref]

Device files, which are used for communication with important system resources, should be labeled with proper SELinux types. If any device files carry the SELinux type `device_t` or `unlabeled_t`, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.
To check for incorrectly labeled device files, run following commands:

    $ sudo find /dev -context *:device_t:* \( -type c -o -type b \) -printf "%p %Z\n"

    $ sudo find /dev -context *:unlabeled_t:* \( -type c -o -type b \) -printf "%p %Z\n"

It should produce no output in a well-configured system.
Warning: Automatic remediation of this control is not available. The remediation can be achieved by amending SELinux policy.

Rationale: | If a device file carries the SELinux type `device_t` or `unlabeled_t`, then SELinux cannot properly restrict access to the device file.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_selinux_all_devicefiles_labeled

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 2, 3, 5, 6, 7, 8, 9, APO01.06, APO11.04, BAI01.06, BAI03.05, BAI06.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.03, DSS03.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01, 3.1.2, 3.1.5, 3.7.2, CCI-000022, CCI-000032, CCI-000318, CCI-000366, CCI-000368, CCI-001812, CCI-001813, CCI-001814, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 6.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.14.2.7, A.15.2.1, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6, DE.CM-1, DE.CM-7, PR.AC-4, PR.DS-5, PR.IP-1, PR.IP-3, PR.PT-1, PR.PT-3, SRG-OS-000480-GPOS-00227, OL07-00-020900, SV-221740r603260_rule

#### Rule Ensure No Daemons are Unconfined by SELinux [ref]

Daemons for which the SELinux policy does not contain rules will inherit the context of the parent process. Because daemons are launched during startup and descend from the `init` process, they inherit the `unconfined_service_t` context.
To check for unconfined daemons, run the following command:

    $ sudo ps -eZ | grep "unconfined_service_t"

It should produce no output in a well-configured system.
Warning: Automatic remediation of this control is not available. Remediation can be achieved by amending SELinux policy or stopping the unconfined daemons as outlined above.

Rationale: | Daemons which run with the `unconfined_service_t` context may cause AVC denials, or allow privileges that the daemon does not require.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_selinux_confinement_of_daemons

Identifiers and References

References: 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 6, 9, APO01.06, APO11.04, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.06, MEA02.01, 3.1.2, 3.1.5, 3.7.2, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-7(a), CM-7(b), CM-6(a), AC-3(3)(a), AC-6, PR.AC-4, PR.DS-5, PR.IP-1, PR.PT-1, PR.PT-3, 1.2.6

#### Rule Configure SELinux Policy [ref]

The SELinux `targeted` policy is appropriate for general-purpose desktops and servers, as well as systems in many other roles. To configure the system to use this policy, add or correct the following line in `/etc/selinux/config`:

    SELINUXTYPE=targeted

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

Rationale:

Setting the SELinux policy to `targeted` or a more specialized policy ensures the system will confine processes that are likely to be targeted for exploitation, such as network or system services.
Note: During the development or debugging of SELinux modules, it is common to temporarily place non-production systems in `permissive` mode. In such temporary cases, SELinux policies should be developed, and once work is completed, the system should be reconfigured to `targeted`.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_selinux_policytype

Identifiers and References

References: BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, 1.2.6, SRG-OS-000445-GPOS-00199, SRG-APP-000233-CTR-000585, OL07-00-020220, SV-228570r853732_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinux_policy_name='targeted'

    if [ -e "/etc/selinux/config" ] ; then

        LC_ALL=C sed -i "/^SELINUXTYPE=/Id" "/etc/selinux/config"
    else
        touch "/etc/selinux/config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/selinux/config"

    cp "/etc/selinux/config" "/etc/selinux/config.bak"
    # Insert at the end of the file
    printf '%s\n' "SELINUXTYPE=$var_selinux_policy_name" >> "/etc/selinux/config"
    # Clean up after ourselves.
    rm "/etc/selinux/config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    - name: XCCDF Value var_selinux_policy_name # promote to variable
      set_fact:
        var_selinux_policy_name: !!str targeted
      tags:
        - always

    - name: Configure SELinux Policy
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUXTYPE=
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/selinux/config
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUXTYPE=
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/selinux/config
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUXTYPE=
          line: SELINUXTYPE={{ var_selinux_policy_name }}
          state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020220
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - NIST-800-53-AU-9
      - NIST-800-53-SC-7(21)
      - PCI-DSSv4-1.2.6
      - low_complexity
      - low_disruption
      - medium_severity
      - reboot_required
      - restrict_strategy
      - selinux_policytype

#### Rule Ensure SELinux State is Enforcing [ref]

The SELinux state should be set to `enforcing` at system boot time. In the file `/etc/selinux/config`, add or correct the following line to configure the system to boot into enforcing mode:

    SELINUX=enforcing

Rationale: | Setting the SELinux state to enforcing ensures SELinux is able to confine potentially compromised processes to the security policy, which is designed to prevent them from causing damage to the system or further elevating their privileges.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_selinux_state

Identifiers and References

References: BP28(R4), BP28(R66), 1, 11, 12, 13, 14, 15, 16, 18, 3, 4, 5, 6, 8, 9, APO01.06, APO11.04, APO13.01, BAI03.05, DSS01.05, DSS03.01, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, MEA02.01, 3.1.2, 3.7.2, CCI-001084, CCI-002165, CCI-002696, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.2.3.4, 4.3.3.2.2, 4.3.3.3.9, 4.3.3.4, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, 4.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.1, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, A.13.1.1, A.13.1.2, A.13.1.3, A.13.2.1, A.13.2.2, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.2, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-004-6 R3.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CIP-007-3 R6.5, AC-3, AC-3(3)(a), AU-9, SC-7(21), DE.AE-1, ID.AM-3, PR.AC-4, PR.AC-5, PR.AC-6, PR.DS-5, PR.PT-1, PR.PT-3, PR.PT-4, SRG-OS-000445-GPOS-00199, SRG-OS-000134-GPOS-00068, OL07-00-020210, SV-221716r853675_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | true
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_selinux_state='enforcing'

    if [ -e "/etc/selinux/config" ] ; then

        LC_ALL=C sed -i "/^SELINUX=/Id" "/etc/selinux/config"
    else
        touch "/etc/selinux/config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/selinux/config"

    cp "/etc/selinux/config" "/etc/selinux/config.bak"
    # Insert at the end of the file
    printf '%s\n' "SELINUX=$var_selinux_state" >> "/etc/selinux/config"
    # Clean up after ourselves.
    rm "/etc/selinux/config.bak"

    fixfiles onboot
    fixfiles -f relabel

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_selinux_state # promote to variable
      set_fact:
        var_selinux_state: !!str enforcing
      tags:
        - always

    - name: Ensure SELinux State is Enforcing
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUX=
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/selinux/config
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUX=
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/selinux/config
        lineinfile:
          path: /etc/selinux/config
          create: true
          regexp: ^SELINUX=
          line: SELINUX={{ var_selinux_state }}
          state: present
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-020210
      - NIST-800-171-3.1.2
      - NIST-800-171-3.7.2
      - NIST-800-53-AC-3
      - NIST-800-53-AC-3(3)(a)
      - NIST-800-53-AU-9
      - NIST-800-53-SC-7(21)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy
      - selinux_state

Group Services Group contains 23 groups and 54 rules

[ref] The best protection against vulnerable software is running less software. This section describes how to review the software which Oracle Linux 7 installs on a system and disable software which is not needed. It then enumerates the software packages installed on a default Oracle Linux 7 system and provides guidance about which ones can be safely disabled.
Oracle Linux 7 provides a convenient minimal install option that essentially installs the bare necessities for a functional system. When building Oracle Linux 7 systems, it is highly recommended to select the minimal packages and then build up the system from there.

Group Base Services Group contains 2 rules
[ref] This section addresses the base services that are installed on a Oracle Linux 7 default installation which are not covered in other sections. Some of these services listen on the network and should be treated with particular discretion. Other services are local system utilities that may or may not be extraneous. In general, system services should be disabled if not required.

#### Rule Uninstall Automatic Bug Reporting Tool (abrt) [ref]

The Automatic Bug Reporting Tool (`abrt`) collects and reports crash data when an application crash is detected. Using a variety of plugins, abrt can email crash reports to system administrators, log crash reports to files, or forward crash reports to a centralized issue tracking system such as RHTSupport. The `abrt` package can be removed with the following command:

    $ sudo yum erase abrt

Rationale: | Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the system, as well as sensitive information from within a process's address space or registers.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_abrt_removed
Identifiers and References | References: CCI-000381, SRG-OS-000095-GPOS-00049

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove abrt
    #	   from the system, and may remove any packages
    #	   that depend on abrt. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "abrt" ; then

        yum remove -y "abrt"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=abrt

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure abrt is removed
      package:
        name: abrt
        state: absent
      tags:
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_abrt_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_abrt

    class remove_abrt {
      package { 'abrt':
        ensure => 'purged',
      }
    }

#### Rule Disable KDump Kernel Crash Analyzer (kdump) [ref]

The `kdump` service provides a kernel crash dump analyzer. It uses the `kexec` system call to boot a secondary kernel ("capture" kernel) following a system crash, which can load information from the crashed kernel for analysis. The `kdump` service can be disabled with the following command:

    $ sudo systemctl mask --now kdump.service

Rationale: | Kernel core dumps may contain the full contents of system memory at the time of the crash. Kernel core dumps consume a considerable amount of disk space and may result in denial of service by exhausting the available space on the target file system partition. Unless the system is used for kernel development or testing, there is little need to run the kdump service.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_kdump_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000366, CCI-001665, 164.308(a)(1)(ii)(D), 164.308(a)(3), 164.308(a)(4), 164.310(b), 164.310(c), 164.312(a), 164.312(e), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, FMT_SMF_EXT.1.1, SRG-OS-000269-GPOS-00103, SRG-OS-000480-GPOS-00227, OL07-00-021300, SV-221753r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'kdump.service'
    "$SYSTEMCTL_EXEC" disable 'kdump.service'
    "$SYSTEMCTL_EXEC" mask 'kdump.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files kdump.socket; then
        "$SYSTEMCTL_EXEC" stop 'kdump.socket'
        "$SYSTEMCTL_EXEC" mask 'kdump.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'kdump.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

    kdump --disable

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service kdump
      block:

      - name: Disable service kdump
        block:

        - name: Disable service kdump
          systemd:
            name: kdump.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service kdump' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021300
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_kdump_disabled

    - name: Unit Socket Exists - kdump.socket
      command: systemctl -q list-unit-files kdump.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021300
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_kdump_disabled

    - name: Disable socket kdump
      systemd:
        name: kdump.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("kdump.socket",multiline=True)
      tags:
      - DISA-STIG-OL07-00-021300
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_kdump_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["kdump"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_kdump

    class disable_kdump {
      service {'kdump':
        enable => false,
        ensure => 'stopped',
      }
    }

Group Cron and At Daemons Group contains 1 group and 3 rules
[ref] The cron and at services are used to allow commands to be executed at a later time. The cron service is required by almost all systems to perform necessary maintenance tasks, while at may or may not be required on a given system. Both daemons should be configured defensively.
Group Restrict at and cron to Authorized Users if Necessary Group contains 2 rules

[ref] The `/etc/cron.allow` and `/etc/at.allow` files contain lists of users who are allowed to use `cron` and at to delay execution of processes. If these files exist and if the corresponding files `/etc/cron.deny` and `/etc/at.deny` do not exist, then only users listed in the relevant allow files can run the crontab and `at` commands to submit jobs to be run at scheduled intervals. On many systems, only the system administrator needs the ability to schedule jobs. Note that even if a given user is not listed in `cron.allow`, cron jobs can still be run as that user. The `cron.allow` file controls only administrative access to the crontab command for scheduling and modifying cron jobs.
To restrict `at` and `cron` to only authorized users:

- Remove the `cron.deny` file:

      $ sudo rm /etc/cron.deny

- Edit `/etc/cron.allow`, adding one line for each user allowed to use the crontab command to create cron jobs.
- Remove the `at.deny` file:

      $ sudo rm /etc/at.deny

- Edit `/etc/at.allow`, adding one line for each user allowed to use the at command to create at jobs.

#### Rule Verify Group Who Owns /etc/cron.allow file [ref]

If `/etc/cron.allow` exists, it must be group-owned by `root`. To properly set the group owner of `/etc/cron.allow`, run the command:

    $ sudo chgrp root /etc/cron.allow

Rationale: | If the owner of the cron.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_groupowner_cron_allow

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-021120, SV-221752r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    chgrp 0 /etc/cron.allow

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Test for existence /etc/cron.allow
      stat:
        path: /etc/cron.allow
      register: file_exists
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021120
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_groupowner_cron_allow
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure group owner 0 on /etc/cron.allow
      file:
        path: /etc/cron.allow
        group: '0'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - file_exists.stat is defined and file_exists.stat.exists
      tags:
      - DISA-STIG-OL07-00-021120
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_groupowner_cron_allow
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Verify User Who Owns /etc/cron.allow file [ref]

If `/etc/cron.allow` exists, it must be owned by `root`. To properly set the owner of `/etc/cron.allow`, run the command:

    $ sudo chown root /etc/cron.allow

Rationale: | If the owner of the cron.allow file is not set to root, the possibility exists for an unauthorized user to view or edit sensitive information.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_owner_cron_allow

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-021110, SV-221751r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    chown 0 /etc/cron.allow

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Test for existence /etc/cron.allow
      stat:
        path: /etc/cron.allow
      register: file_exists
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021110
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - configure_strategy
      - file_owner_cron_allow
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Ensure owner 0 on /etc/cron.allow
      file:
        path: /etc/cron.allow
        owner: '0'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - file_exists.stat is defined and file_exists.stat.exists
      tags:
      - DISA-STIG-OL07-00-021110
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - configure_strategy
      - file_owner_cron_allow
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Enable cron Service [ref]

The `crond` service is used to execute commands at preconfigured times. It is required by almost all systems to perform necessary maintenance tasks, such as notifying root of system activity. The `crond` service can be enabled with the following command:

    $ sudo systemctl enable crond.service

Rationale: | Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_crond_enabled

Identifiers and References

References: 11, 14, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS06.06, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.9.1.2, CM-6(a), PR.IP-1, PR.PT-3

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" unmask 'crond.service'
    "$SYSTEMCTL_EXEC" start 'crond.service'
    "$SYSTEMCTL_EXEC" enable 'crond.service'

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Enable service crond
      block:

      - name: Gather the package facts
        package_facts:
          manager: auto

      - name: Enable service crond
        systemd:
          name: crond
          enabled: 'yes'
          state: started
          masked: 'no'
        when:
        - '"cronie" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_crond_enabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    enabled = ["crond"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include enable_crond

    class enable_crond {
      service {'crond':
        enable => true,
        ensure => 'running',
      }
    }

Group LDAP Group contains 1 group and 1 rule
[ref] LDAP is a popular directory service, that is, a standardized way of looking up information from a central database. Oracle Linux 7 includes software that enables a system to act as both an LDAP client and server.
Group Configure OpenLDAP Clients Group contains 1 rule

[ref] This section provides information on which security settings are important to configure in OpenLDAP clients by manually editing the appropriate configuration files. Oracle Linux 7 provides an automated configuration tool called authconfig and a graphical wrapper for authconfig called `system-config-authentication`. However, these tools do not provide as much control over configuration as manual editing of configuration files. The authconfig tools do not allow you to specify locations of SSL certificate files, which is useful when trying to use SSL cleanly across several protocols. Installation and configuration of OpenLDAP on Oracle Linux 7 is available at https://docs.oracle.com/en/operating-systems/oracle-linux/7/userauth/userauth-AuthenticationConfiguration.html#ol7-s7-auth.
Warning: Before configuring any system to be an LDAP client, ensure that a working LDAP server is present on the network.

#### Rule Configure LDAP Client to Use TLS For All Transactions [ref]

This check verifies cryptography has been implemented to protect the integrity of remote LDAP authentication sessions.
To determine if LDAP is being used for authentication, use the following command:

    $ sudo grep -i useldapauth /etc/sysconfig/authconfig

If `USELDAPAUTH=yes`, then LDAP is being used. To check if LDAP is configured to use TLS, use the following command:

    $ sudo grep -i ssl /etc/pam_ldap.conf

Rationale: | Without cryptographic integrity protections, information can be altered by unauthorized users without detection. The ssl directive specifies whether to use TLS or not. If not specified it will default to no. It should be set to start_tls rather than doing LDAP over SSL.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_ldap_client_start_tls

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001453, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, AC-17(a), AC-17(2), CM-6(a), SC-12(a), SC-12(b), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, SRG-OS-000250-GPOS-00093

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q nss-pam-ldapd; then

    # Use LDAP for authentication
    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^USELDAPAUTH")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s=%s" "$stripped_key" "yes"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^USELDAPAUTH\\>" "/etc/sysconfig/authconfig"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^USELDAPAUTH\\>.*/$escaped_formatted_output/gi" "/etc/sysconfig/authconfig"
    else
        if [[ -s "/etc/sysconfig/authconfig" ]] && [[ -n "$(tail -c 1 -- "/etc/sysconfig/authconfig" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/sysconfig/authconfig"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/sysconfig/authconfig"
    fi

    # Configure client to use TLS for all authentications
    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^ssl")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "start_tls"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^ssl\\>" "/etc/nslcd.conf"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^ssl\\>.*/$escaped_formatted_output/gi" "/etc/nslcd.conf"
    else
        if [[ -s "/etc/nslcd.conf" ]] && [[ -n "$(tail -c 1 -- "/etc/nslcd.conf" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/nslcd.conf"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/nslcd.conf"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Group NFS and RPC Group contains 5 groups and 5 rules

[ref] The Network File System is a popular distributed filesystem for the Unix environment, and is very widely deployed. This section discusses the circumstances under which it is possible to disable NFS and its dependencies, and then details steps which should be taken to secure NFS's configuration. This section is relevant to systems operating as NFS clients, as well as to those operating as NFS servers.

Group Disable All NFS Services if Possible Group contains 1 group and 1 rule
[ref] If there is not a reason for the system to operate as either an NFS client or an NFS server, follow all instructions in this section to disable subsystems required by NFS. Warning: The steps in this section will prevent a system from operating as either an NFS client or an NFS server. Only perform these steps on systems which do not need NFS at all.
Group Disable Services Used Only by NFS Group contains 1 rule
[ref] If NFS is not needed, disable the NFS client daemons nfslock, rpcgssd, and rpcidmapd. All of these daemons run with elevated privileges, and many listen for network connections. If they are not needed, they should be disabled to improve system security posture.

#### Rule Disable rpcbind Service [ref]

The rpcbind utility maps RPC services to the ports on which they listen. RPC processes notify rpcbind when they start, registering the ports they are listening on and the RPC program numbers they expect to serve. The rpcbind service redirects the client to the proper port number so it can communicate with the requested service. If the system does not require RPC (such as for NFS servers) then this service should be disabled. The `rpcbind` service can be disabled with the following command:

    $ sudo systemctl mask --now rpcbind.service

Rationale: | If the system does not require rpc based services, it is recommended that rpcbind be disabled to reduce the attack surface.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_service_rpcbind_disabled
Identifiers and References | References: 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'rpcbind.service'
    "$SYSTEMCTL_EXEC" disable 'rpcbind.service'
    "$SYSTEMCTL_EXEC" mask 'rpcbind.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files rpcbind.socket; then
        "$SYSTEMCTL_EXEC" stop 'rpcbind.socket'
        "$SYSTEMCTL_EXEC" mask 'rpcbind.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'rpcbind.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service rpcbind
      block:

      - name: Disable service rpcbind
        block:

        - name: Disable service rpcbind
          systemd:
            name: rpcbind.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service rpcbind' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - service_rpcbind_disabled

    - name: Unit Socket Exists - rpcbind.socket
      command: systemctl -q list-unit-files rpcbind.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - service_rpcbind_disabled

    - name: Disable socket rpcbind
      systemd:
        name: rpcbind.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("rpcbind.socket",multiline=True)
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - service_rpcbind_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["rpcbind"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_rpcbind

    class disable_rpcbind {
      service {'rpcbind':
        enable => false,
        ensure => 'stopped',
      }
    }

Group Configure NFS Clients Group contains 1 group and 3 rules
[ref] The steps in this section are appropriate for systems which operate as NFS clients.
Group Mount Remote Filesystems with Restrictive Options Group contains 3 rules

[ref] Edit the file `/etc/fstab`. For each filesystem whose type (column 3) is `nfs` or `nfs4`, add the text `,nodev,nosuid` to the list of mount options in column 4. If appropriate, also add `,noexec`.
See the section titled "Restrict Partition Mount Options" for a description of the effects of these options. In general, execution of files mounted via NFS should be considered risky because of the possibility that an adversary could intercept the request and substitute a malicious file. Allowing setuid files to be executed from remote servers is particularly risky, both for this reason and because it requires the clients to extend root-level trust to the NFS server.

#### Rule Mount Remote Filesystems with Kerberos Security [ref]

Add the `sec=krb5:krb5i:krb5p` option to the fourth column of `/etc/fstab` for the line which controls mounting of any NFS mounts.
Rationale: | When an NFS server is configured to use AUTH_SYS a selected userid and groupid are used to handle requests from the remote user. The userid and groupid could mistakenly or maliciously be set incorrectly. The AUTH_GSS method of authentication uses certificates on the server and client systems to more securely authenticate the remote mount request.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_krb_sec_remote_filesystems

Identifiers and References

References: 1, 12, 14, 15, 16, 18, 3, 5, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.3, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.6.1.2, A.9.1.2, A.9.2.1, A.9.2.3, A.9.2.4, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), IA-2, IA-2(8), IA-2(9), AC-17(a), PR.AC-4, PR.AC-7, SRG-OS-000480-GPOS-00227, OL07-00-040750, SV-221890r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    vfstype_points=()
    readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

    for vfstype_point in "${vfstype_points[@]}"
    do
        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|sec=krb5:krb5i:krb5p)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="nfs4"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}sec=krb5:krb5i:krb5p 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "sec=krb5:krb5i:krb5p"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,sec=krb5:krb5i:krb5p|" /etc/fstab
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Get nfs and nfs4 mount points, that don't have sec=krb5:krb5i:krb5p
      command: findmnt --fstab --types nfs,nfs4 -O nosec=krb5:krb5i:krb5p -n -P
      register: points_register
      check_mode: false
      changed_when: false
      failed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040750
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_krb_sec_remote_filesystems
      - no_reboot_needed

    - name: Add sec=krb5:krb5i:krb5p to nfs and nfs4 mount points
      mount:
        path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
        src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
        fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
        state: present
        opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},sec=krb5:krb5i:krb5p'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (points_register.stdout | length > 0) and '\\x09' not in item
      with_items: '{{ points_register.stdout_lines }}'
      tags:
      - DISA-STIG-OL07-00-040750
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_krb_sec_remote_filesystems
      - no_reboot_needed

#### Rule Mount Remote Filesystems with nodev [ref]

Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of any NFS mounts.
Rationale: | Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_nodev_remote_filesystems

Identifiers and References

References: 11, 13, 14, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.05, DSS05.06, DSS06.06, CCI-000366, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, A.11.2.9, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.8.2.1, A.8.2.2, A.8.2.3, A.8.3.1, A.8.3.3, A.9.1.2, CM-6(a), MP-2, PR.IP-1, PR.PT-2, PR.PT-3, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    vfstype_points=()
    readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

    for vfstype_point in "${vfstype_points[@]}"
    do
        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nodev)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="nfs4"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}nodev 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nodev"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nodev|" /etc/fstab
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Get nfs and nfs4 mount points, that don't have nodev
      command: findmnt --fstab --types nfs,nfs4 -O nonodev -n -P
      register: points_register
      check_mode: false
      changed_when: false
      failed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-MP-2
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_nodev_remote_filesystems
      - no_reboot_needed

    - name: Add nodev to nfs and nfs4 mount points
      mount:
        path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
        src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
        fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
        state: present
        opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},nodev'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (points_register.stdout | length > 0) and '\\x09' not in item
      with_items: '{{ points_register.stdout_lines }}'
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-MP-2
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_nodev_remote_filesystems
      - no_reboot_needed

#### Rule Mount Remote Filesystems with nosuid [ref]

Add the `nosuid` option to the fourth column of `/etc/fstab` for the line which controls mounting of any NFS mounts.
Rationale: | NFS mounts should not present suid binaries to users. Only vendor-supplied suid executables should be installed to their default location on the local filesystem.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_mount_option_nosuid_remote_filesystems

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-6, AC-6(1), CM6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-021020, SV-221743r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    vfstype_points=()
    readarray -t vfstype_points < <(grep -E "[[:space:]]nfs[4]?[[:space:]]" /etc/fstab | awk '{print $2}')

    for vfstype_point in "${vfstype_points[@]}"
    do
        mount_point_match_regexp="$(printf "^[[:space:]]*[^#].*[[:space:]]%s[[:space:]]" ${vfstype_point//\\/\\\\})"

        # If the mount point is not in /etc/fstab, get previous mount options from /etc/mtab
        if ! grep -q "$mount_point_match_regexp" /etc/fstab; then
            # runtime opts without some automatic kernel/userspace-added defaults
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/mtab | head -1 |  awk '{print $4}' \
                        | sed -E "s/(rw|defaults|seclabel|nosuid)(,|$)//g;s/,$//")
            [ "$previous_mount_opts" ] && previous_mount_opts+=","
            # In iso9660 filesystems mtab could describe a "blocksize" value, this should be reflected in
            # fstab as "block".  The next variable is to satisfy shellcheck SC2050.
            fs_type="nfs4"
            if [  "$fs_type" == "iso9660" ] ; then
                previous_mount_opts=$(sed 's/blocksize=/block=/' <<< "$previous_mount_opts")
            fi
            echo " ${vfstype_point//\\/\\\\} nfs4 defaults,${previous_mount_opts}nosuid 0 0" >> /etc/fstab
        # If the mount_opt option is not already in the mount point's /etc/fstab entry, add it
        elif ! grep "$mount_point_match_regexp" /etc/fstab | grep -q "nosuid"; then
            previous_mount_opts=$(grep "$mount_point_match_regexp" /etc/fstab | awk '{print $4}')
            sed -i "s|\(${mount_point_match_regexp}.*${previous_mount_opts}\)|\1,nosuid|" /etc/fstab
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Get nfs and nfs4 mount points, that don't have nosuid
      command: findmnt --fstab --types nfs,nfs4 -O nonosuid -n -P
      register: points_register
      check_mode: false
      changed_when: false
      failed_when: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-021020
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM6(a)
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_nosuid_remote_filesystems
      - no_reboot_needed

    - name: Add nosuid to nfs and nfs4 mount points
      mount:
        path: '{{ item | regex_search(''TARGET="([^"]+)"'',''\1'') | first }}'
        src: '{{ item | regex_search(''SOURCE="([^"]+)"'',''\1'') | first }}'
        fstype: '{{ item | regex_search(''FSTYPE="([^"]+)"'',''\1'') | first }}'
        state: present
        opts: '{{ item | regex_search(''OPTIONS="([^"]+)"'',''\1'') | first }},nosuid'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - (points_register.stdout | length > 0) and '\\x09' not in item
      with_items: '{{ points_register.stdout_lines }}'
      tags:
      - DISA-STIG-OL07-00-021020
      - NIST-800-53-AC-6
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM6(a)
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - mount_option_nosuid_remote_filesystems
      - no_reboot_needed

Group Configure NFS Servers Group contains 1 rule
[ref] The steps in this section are appropriate for systems which operate as NFS servers.

#### Rule Use Kerberos Security on All Exports [ref]

Using Kerberos on all exported mounts prevents a malicious client or user from impersonating a system user. To cryptography authenticate users to the NFS server, add `sec=krb5:krb5i:krb5p` to each export in `/etc/exports`.
Rationale: | When an NFS server is configured to use AUTH_SYS a selected userid and groupid are used to handle requests from the remote user. The userid and groupid could mistakenly or maliciously be set incorrectly. The AUTH_GSS method of authentication uses certificates on the server and client systems to more securely authenticate the remote mount request.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_use_kerberos_security_all_exports

Identifiers and References

References: 1, 12, 14, 15, 16, 18, 3, 5, DSS05.04, DSS05.10, DSS06.10, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.3, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.6.1.2, A.9.1.2, A.9.2.1, A.9.2.3, A.9.2.4, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-7(a), CM-7(b), CM-6(a), IA-2, IA-2(8), IA-2(9), AC-17(a), PR.AC-4, PR.AC-7, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    nfs_exports=()
    readarray -t nfs_exports < <(grep -E "^/.*[[:space:]]+ .*\(.*\)[[:space:]]*$" /etc/exports | awk '{print $2}')

    for nfs_export in "${nfs_exports[@]}"
    do
        correct_export=""
        if [ "$(grep -c "sec=" <<<"$nfs_export")" -eq 0 ]; then
            correct_export="$(echo $nfs_export|sed  -e 's/).*$/,sec=krb5\:krb5i\:krb5p)/')"
        else
            correct_export="$(echo $nfs_export|sed  -e 's/sec=[^\,\)]*/sec=krb5\:krb5i\:krb5p/')"
        fi
        sed -i "s|$nfs_export|$correct_export|g" /etc/exports
    done

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Drop any security clause for every export
      replace:
        path: /etc/exports
        regexp: ^(/.*\w+.*\(.*),sec=[^,]*(.*\)\w*$)
        replace: \1\2
      tags:
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - use_kerberos_security_all_exports

    - name: Add kerberos security when no security is defined for an export
      replace:
        path: /etc/exports
        regexp: ^(/.*\w+.*\(.*)(\)\w*$)
        replace: \1,sec=krb5:krb5i:krb5p\2
      tags:
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-2(8)
      - NIST-800-53-IA-2(9)
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - use_kerberos_security_all_exports

Group Network Time Protocol Group contains 3 rules

[ref] The Network Time Protocol is used to manage the system clock over a network. Computer clocks are not very accurate, so time will drift unpredictably on unmanaged systems. Central time protocols can be used both to ensure that time is consistent among a network of systems, and that their time is consistent with the outside world.
If every system on a network reliably reports the same time, then it is much easier to correlate log messages in case of an attack. In addition, a number of cryptographic protocols (such as Kerberos) use timestamps to prevent certain types of attacks. If your network does not have synchronized time, these protocols may be unreliable or even unusable.
Depending on the specifics of the network, global time accuracy may be just as important as local synchronization, or not very important at all. If your network is connected to the Internet, using a public timeserver (or one provided by your enterprise) provides globally accurate timestamps which may be essential in investigating or responding to an attack which originated outside of your network.
A typical network setup involves a small number of internal systems operating as NTP servers, and the remainder obtaining time information from those internal servers.
There is a choice between the daemons `ntpd` and `chronyd`, which are available from the repositories in the `ntp` and `chrony` packages respectively.
The default `chronyd` daemon can work well when external time references are only intermittently accesible, can perform well even when the network is congested for longer periods of time, can usually synchronize the clock faster and with better time accuracy, and quickly adapts to sudden changes in the rate of the clock, for example, due to changes in the temperature of the crystal oscillator. `Chronyd` should be considered for all systems which are frequently suspended or otherwise intermittently disconnected and reconnected to a network. Mobile and virtual systems for example.
The `ntpd` NTP daemon fully supports NTP protocol version 4 (RFC 5905), including broadcast, multicast, manycast clients and servers, and the orphan mode. It also supports extra authentication schemes based on public-key cryptography (RFC 5906). The NTP daemon (`ntpd`) should be considered for systems which are normally kept permanently on. Systems which are required to use broadcast or multicast IP, or to perform authentication of packets with the `Autokey` protocol, should consider using `ntpd`.
Refer to https://docs.oracle.com/en/operating-systems/oracle-linux/7/network/ol7-nettime.html for more detailed comparison of features of `chronyd` and `ntpd` daemon features respectively, and for further guidance how to choose between the two NTP daemons.
The upstream manual pages at https://chrony-project.org/documentation.html for `chronyd` and http://www.ntp.org for `ntpd` provide additional information on the capabilities and configuration of each of the NTP daemons.

#### Rule Enable the NTP Daemon [ref]

Run the following command to determine the current status of the `chronyd` service:

    $ sudo systemctl is-active chronyd

If the service is running, it should return the following:

    active

Note: The `chronyd` daemon is enabled by default.
Run the following command to determine the current status of the `ntpd` service:

    $ sudo systemctl is-active ntpd

If the service is running, it should return the following:

    active

Note: The `ntpd` daemon is not enabled by default. Though as mentioned in the previous sections in certain environments the `ntpd` daemon might be preferred to be used rather than the `chronyd` one. Refer to: https://docs.oracle.com/en/operating-systems/oracle-linux/7/network/ol7-nettime.html for guidance which NTP daemon to choose depending on the environment used.

Rationale:

Enabling some of `chronyd` or `ntpd` services ensures that the NTP daemon will be running and that the system will synchronize its time to any servers specified. This is important whether the system is configured to be a client (and synchronize only its own clock) or it is also acting as an NTP server to other systems. Synchronizing time is essential for authentication services such as Kerberos, but it is also important for maintaining accurate logs and auditing possible security breaches.
The `chronyd` and `ntpd` NTP daemons offer all of the functionality of `ntpdate`, which is now deprecated.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_chronyd_or_ntpd_enabled
Identifiers and References | References: BP28(R71), 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 3.3.7, CCI-000160, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, 0988, 1405, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(a), AU-12(1), PR.PT-1, Req-10.4.1, 10.6.1, SRG-APP-000116-CTR-000235

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if rpm --quiet -q "chrony" ; then
        if ! /usr/sbin/pidof ntpd ; then
            /usr/bin/systemctl enable "chronyd"
            /usr/bin/systemctl start "chronyd"
            # The service may not be running because it has been started and failed,
            # so let's reset the state so OVAL checks pass.
            # Service should be 'inactive', not 'failed' after reboot though.
            if /usr/bin/systemctl --failed | grep -q "chronyd"; then
                /usr/bin/systemctl reset-failed "chronyd"
            fi
        fi
    elif rpm --quiet -q "ntp" ; then
        /usr/bin/systemctl enable "ntpd"
        /usr/bin/systemctl start "ntpd"
        # The service may not be running because it has been started and failed,
        # so let's reset the state so OVAL checks pass.
        # Service should be 'inactive', not 'failed' after reboot though.
        if /usr/bin/systemctl --failed | grep -q "ntpd"; then
            /usr/bin/systemctl reset-failed "ntpd"
        fi
    else
        if ! rpm -q --quiet "chrony" ; then
            yum install -y "chrony"
        fi
        /usr/bin/systemctl enable "chronyd"
        /usr/bin/systemctl start "chronyd"
        # The service may not be running because it has been started and failed,
        # so let's reset the state so OVAL checks pass.
        # Service should be 'inactive', not 'failed' after reboot though.
        if /usr/bin/systemctl --failed | grep -q "chronyd"; then
            /usr/bin/systemctl reset-failed "chronyd"
        fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-171-3.3.7
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.1
      - PCI-DSSv4-10.6.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_chronyd_or_ntpd_enabled

    - name: Gather the package facts
      ansible.builtin.package_facts:
        manager: auto
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.3.7
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.1
      - PCI-DSSv4-10.6.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_chronyd_or_ntpd_enabled

    - name: Start ntpd service if ntp installed
      systemd:
        name: ntpd
        enabled: 'yes'
        state: started
        masked: 'no'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - '''ntp'' in ansible_facts.packages'
      tags:
      - NIST-800-171-3.3.7
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.1
      - PCI-DSSv4-10.6.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_chronyd_or_ntpd_enabled

    - name: Start chronyd service if chrony or chronyd installed
      systemd:
        name: chronyd
        enabled: 'yes'
        state: started
        masked: 'no'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ('chrony' in ansible_facts.packages) or ('chronyd' in ansible_facts.packages)
      tags:
      - NIST-800-171-3.3.7
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.1
      - PCI-DSSv4-10.6.1
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_chronyd_or_ntpd_enabled

#### Rule Specify Additional Remote NTP Servers [ref]

Depending on specific functional requirements of a concrete production environment, the Oracle Linux 7 system can be configured to utilize the services of the `chronyd` NTP daemon (the default), or services of the `ntpd` NTP daemon. Refer to https://docs.oracle.com/en/operating-systems/oracle-linux/7/network/ol7-nettime.html for more detailed comparison of the features of both of the choices, and for further guidance how to choose between the two NTP daemons.
Additional NTP servers can be specified for time synchronization. To do so, perform the following:

- if the system is configured to use the `chronyd` as the NTP daemon (the default), edit the file `/etc/chrony.conf` as follows,
- if the system is configured to use the `ntpd` as the NTP daemon, edit the file `/etc/ntp.conf` as documented below.

Add additional lines of the following form, substituting the IP address or hostname of a remote NTP server for ntpserver:

    server ntpserver

Rationale: | Specifying additional NTP servers increases the availability of accurate time data, in the event that one of the specified servers becomes unavailable. This is typical for a system acting as an NTP server for other systems.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_chronyd_or_ntpd_specify_multiple_servers
Identifiers and References | References: 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, 0988, 1405, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(a), AU-8(2), AU-12(1), PR.PT-1, Req-10.4.3

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_multiple_time_servers='0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,3.pool.ntp.org'

    config_file="/etc/ntp.conf"
    /usr/sbin/pidof ntpd || config_file="/etc/chrony.conf"

    if ! [ "$(grep -c '^server' "$config_file")" -gt 1 ] ; then
      if ! grep -q '#[[:space:]]*server' "$config_file" ; then
        for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
          printf '\nserver %s' "$server" >> "$config_file"
        done
      else
        sed -i 's/#[ \t]*server/server/g' "$config_file"
      fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: XCCDF Value var_multiple_time_servers # promote to variable
      set_fact:
        var_multiple_time_servers: !!str 0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,3.pool.ntp.org
      tags:
        - always

    - name: Detect if chrony configuration file is present
      find:
        path: /etc
        patterns: chrony.conf
      register: chrony_server_config
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-AU-8(2)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.3
      - chronyd_or_ntpd_specify_multiple_servers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Configure multiple time servers in chrony config
      lineinfile:
        path: /etc/chrony.conf
        line: server {{ item }}
        state: present
        create: true
      loop: '{{ var_multiple_time_servers.split(",") }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - chrony_server_config.matched == 1
      tags:
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-AU-8(2)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.3
      - chronyd_or_ntpd_specify_multiple_servers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Detect if NTP configuration file is present
      find:
        path: /etc
        patterns: ntp.conf
      register: ntp_server_config
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-AU-8(2)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.3
      - chronyd_or_ntpd_specify_multiple_servers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Configure multiple time servers in NTP config
      lineinfile:
        path: /etc/chrony.conf
        line: pool {{ item }}
        state: present
        create: true
      loop: '{{ var_multiple_time_servers.split(",") }}'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ntp_server_config.matched == 1
      tags:
      - NIST-800-53-AU-12(1)
      - NIST-800-53-AU-8(1)(a)
      - NIST-800-53-AU-8(2)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-10.4.3
      - chronyd_or_ntpd_specify_multiple_servers
      - configure_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Specify a Remote NTP Server [ref]

Depending on specific functional requirements of a concrete production environment, the Oracle Linux 7 system can be configured to utilize the services of the `chronyd` NTP daemon (the default), or services of the `ntpd` NTP daemon. Refer to https://docs.oracle.com/en/operating-systems/oracle-linux/7/network/ol7-nettime.html for more detailed comparison of the features of both of the choices, and for further guidance how to choose between the two NTP daemons.
To specify a remote NTP server for time synchronization, perform the following:

- if the system is configured to use the `chronyd` as the NTP daemon (the default), edit the file `/etc/chrony.conf` as follows,
- if the system is configured to use the `ntpd` as the NTP daemon, edit the file `/etc/ntp.conf` as documented below.

Add or correct the following lines, substituting the IP or hostname of a remote NTP server for ntpserver:

    server ntpserver

This instructs the NTP software to contact that remote server to obtain time data.

Rationale: | Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_chronyd_or_ntpd_specify_remote_server
Identifiers and References | References: 1, 14, 15, 16, 3, 5, 6, APO11.04, BAI03.05, DSS05.04, DSS05.07, MEA02.01, 3.3.7, CCI-000160, CCI-001891, 4.3.3.3.9, 4.3.3.5.8, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 2.10, SR 2.11, SR 2.12, SR 2.8, SR 2.9, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.7.1, CM-6(a), AU-8(1)(a), AU-8(2), AU-12(1), PR.PT-1, Req-10.4.1, Req-10.4.3, SRG-APP-000116-CTR-000235

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { ( [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && ( rpm --quiet -q chrony || rpm --quiet -q ntp ) ); }; then

    var_multiple_time_servers='0.pool.ntp.org,1.pool.ntp.org,2.pool.ntp.org,3.pool.ntp.org'

    config_file="/etc/ntp.conf"
    /usr/sbin/pidof ntpd || config_file="/etc/chrony.conf"

    if ! grep -q ^server "$config_file" ; then
      if ! grep -q '#[[:space:]]*server' "$config_file" ; then
        for server in $(echo "$var_multiple_time_servers" | tr ',' '\n') ; do
          printf '\nserver %s' "$server" >> "$config_file"
        done
      else
        sed -i 's/#[ \t]*server/server/g' "$config_file"
      fi
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Group Obsolete Services Group contains 5 groups and 16 rules

[ref] This section discusses a number of network-visible services which have historically caused problems for system security, and for which disabling or severely limiting the service has been the best available guidance for some time. As a result of this, many of these services are not installed as part of Oracle Linux 7 by default.
Organizations which are running these services should switch to more secure equivalents as soon as possible. If it remains absolutely necessary to run one of these services for legacy reasons, care should be taken to restrict the service as much as possible, for instance by configuring host firewall software such as `iptables` to restrict access to the vulnerable service to only those remote hosts which have a known need to use it.

Group Xinetd Group contains 2 rules
[ref] The `xinetd` service acts as a dedicated listener for some network services (mostly, obsolete ones) and can be used to provide access controls and perform some logging. It has been largely obsoleted by other features, and it is not installed by default. The older Inetd service is not even available as part of Oracle Linux 7.

#### Rule Uninstall xinetd Package [ref]

The `xinetd` package can be removed with the following command:

    $ sudo yum erase xinetd

Rationale: | Removing the `xinetd` package decreases the risk of the xinetd service's accidental (or intentional) activation.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_package_xinetd_removed

Identifiers and References

References: BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # CAUTION: This remediation script will remove xinetd
    #	   from the system, and may remove any packages
    #	   that depend on xinetd. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "xinetd" ; then

        yum remove -y "xinetd"

    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=xinetd

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure xinetd is removed
      package:
        name: xinetd
        state: absent
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - package_xinetd_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_xinetd

    class remove_xinetd {
      package { 'xinetd':
        ensure => 'purged',
      }
    }

#### Rule Disable xinetd Service [ref]

The `xinetd` service can be disabled with the following command:

    $ sudo systemctl mask --now xinetd.service

Rationale: | The xinetd service provides a dedicated listener service for some programs, which is no longer necessary for commonly-used network services. Disabling it ensures that these uncommon services are not running, and also prevents attacks against xinetd itself.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_xinetd_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.4.7, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'xinetd.service'
    "$SYSTEMCTL_EXEC" disable 'xinetd.service'
    "$SYSTEMCTL_EXEC" mask 'xinetd.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files xinetd.socket; then
        "$SYSTEMCTL_EXEC" stop 'xinetd.socket'
        "$SYSTEMCTL_EXEC" mask 'xinetd.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'xinetd.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service xinetd
      block:

      - name: Disable service xinetd
        block:

        - name: Disable service xinetd
          systemd:
            name: xinetd.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service xinetd' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_xinetd_disabled

    - name: Unit Socket Exists - xinetd.socket
      command: systemctl -q list-unit-files xinetd.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_xinetd_disabled

    - name: Disable socket xinetd
      systemd:
        name: xinetd.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("xinetd.socket",multiline=True)
      tags:
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_xinetd_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["xinetd"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_xinetd

    class disable_xinetd {
      service {'xinetd':
        enable => false,
        ensure => 'stopped',
      }
    }

Group NIS Group contains 3 rules
[ref] The Network Information Service (NIS), also known as 'Yellow Pages' (YP), and its successor NIS+ have been made obsolete by Kerberos, LDAP, and other modern centralized authentication services. NIS should not be used because it suffers from security problems inherent in its design, such as inadequate protection of important authentication information.

#### Rule Remove NIS Client [ref]

The Network Information Service (NIS), formerly known as Yellow Pages, is a client-server directory service protocol used to distribute system configuration files. The NIS client (`ypbind`) was used to bind a system to an NIS server and receive the distributed configuration files.
Rationale: | The NIS service is inherently an insecure system that has been vulnerable to DOS attacks, buffer overflows and has poor authentication for querying NIS maps. NIS generally has been replaced by such protocols as Lightweight Directory Access Protocol (LDAP). It is recommended that the service be removed.
Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_package_ypbind_removed
Identifiers and References | References: BP28(R1), 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove ypbind
    #	   from the system, and may remove any packages
    #	   that depend on ypbind. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "ypbind" ; then

        yum remove -y "ypbind"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=ypbind

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure ypbind is removed
      package:
        name: ypbind
        state: absent
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - package_ypbind_removed
      - unknown_severity

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_ypbind

    class remove_ypbind {
      package { 'ypbind':
        ensure => 'purged',
      }
    }

#### Rule Uninstall ypserv Package [ref]

The `ypserv` package can be removed with the following command:

    $ sudo yum erase ypserv

Rationale: | The NIS service provides an unencrypted authentication service which does not provide for the confidentiality and integrity of user passwords or the remote session. Removing the `ypserv` package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_ypserv_removed

Identifiers and References

References: BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, OL07-00-020010, SV-221705r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove ypserv
    #	   from the system, and may remove any packages
    #	   that depend on ypserv. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "ypserv" ; then

        yum remove -y "ypserv"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=ypserv

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure ypserv is removed
      package:
        name: ypserv
        state: absent
      tags:
      - DISA-STIG-OL07-00-020010
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - PCI-DSS-Req-2.2.2
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - package_ypserv_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_ypserv

    class remove_ypserv {
      package { 'ypserv':
        ensure => 'purged',
      }
    }

#### Rule Disable ypbind Service [ref]

The `ypbind` service, which allows the system to act as a client in a NIS or NIS+ domain, should be disabled. The `ypbind` service can be disabled with the following command:

    $ sudo systemctl mask --now ypbind.service

Rationale: | Disabling the `ypbind` service ensures the system is not acting as a client in a NIS or NIS+ domain. This service should be disabled unless in use.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_ypbind_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000305, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'ypbind.service'
    "$SYSTEMCTL_EXEC" disable 'ypbind.service'
    "$SYSTEMCTL_EXEC" mask 'ypbind.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files ypbind.socket; then
        "$SYSTEMCTL_EXEC" stop 'ypbind.socket'
        "$SYSTEMCTL_EXEC" mask 'ypbind.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'ypbind.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service ypbind
      block:

      - name: Disable service ypbind
        block:

        - name: Disable service ypbind
          systemd:
            name: ypbind.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service ypbind' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_ypbind_disabled

    - name: Unit Socket Exists - ypbind.socket
      command: systemctl -q list-unit-files ypbind.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_ypbind_disabled

    - name: Disable socket ypbind
      systemd:
        name: ypbind.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("ypbind.socket",multiline=True)
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_ypbind_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["ypbind"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_ypbind

    class disable_ypbind {
      service {'ypbind':
        enable => false,
        ensure => 'stopped',
      }
    }

Group Rlogin, Rsh, and Rexec Group contains 6 rules
[ref] The Berkeley r-commands are legacy services which allow cleartext remote access and have an insecure trust model.

#### Rule Uninstall rsh-server Package [ref]

The `rsh-server` package can be removed with the following command:

    $ sudo yum erase rsh-server

Rationale:

The `rsh-server` service provides unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session and has very weak authentication. If a privileged user were to login using this service, the privileged user password could be compromised. The `rsh-server` package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.

Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_rsh-server_removed

Identifiers and References

References: BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, 2.2.4, SRG-OS-000095-GPOS-00049, OL07-00-020000, SV-221704r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove rsh-server
    #	   from the system, and may remove any packages
    #	   that depend on rsh-server. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "rsh-server" ; then

        yum remove -y "rsh-server"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=rsh-server

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure rsh-server is removed
      package:
        name: rsh-server
        state: absent
      tags:
      - DISA-STIG-OL07-00-020000
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - package_rsh-server_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_rsh-server

    class remove_rsh-server {
      package { 'rsh-server':
        ensure => 'purged',
      }
    }

#### Rule Uninstall rsh Package [ref]

The `rsh` package contains the client commands for the rsh services

Rationale:

These legacy clients contain numerous security exposures and have been replaced with the more secure SSH package. Even if the server is removed, it is best to ensure the clients are also removed to prevent users from inadvertently attempting to use these commands and therefore exposing their credentials. Note that removing the `rsh` package removes the clients for `rsh`,`rcp`, and `rlogin`.

Severity: | unknown
Rule ID: | xccdf_org.ssgproject.content_rule_package_rsh_removed
Identifiers and References | References: BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3, 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove rsh
    #	   from the system, and may remove any packages
    #	   that depend on rsh. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "rsh" ; then

        yum remove -y "rsh"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=rsh

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure rsh is removed
      package:
        name: rsh
        state: absent
      tags:
      - NIST-800-171-3.1.13
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - package_rsh_removed
      - unknown_severity

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_rsh

    class remove_rsh {
      package { 'rsh':
        ensure => 'purged',
      }
    }

#### Rule Disable rexec Service [ref]

The `rexec` service, which is available with the `rsh-server` package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set `disable` to `yes` in `/etc/xinetd.d/rexec`. The `rexec` socket can be disabled with the following command:

    $ sudo systemctl mask --now rexec.socket

Rationale: | The rexec service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_service_rexec_disabled

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, 3.1.13, 3.4.7, CCI-000068, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'rexec.service'
    "$SYSTEMCTL_EXEC" disable 'rexec.service'
    "$SYSTEMCTL_EXEC" mask 'rexec.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files rexec.socket; then
        "$SYSTEMCTL_EXEC" stop 'rexec.socket'
        "$SYSTEMCTL_EXEC" mask 'rexec.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'rexec.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service rexec
      block:

      - name: Disable service rexec
        block:

        - name: Disable service rexec
          systemd:
            name: rexec.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service rexec' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rexec_disabled

    - name: Unit Socket Exists - rexec.socket
      command: systemctl -q list-unit-files rexec.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rexec_disabled

    - name: Disable socket rexec
      systemd:
        name: rexec.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("rexec.socket",multiline=True)
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rexec_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["rexec"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_rexec

    class disable_rexec {
      service {'rexec':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Disable rlogin Service [ref]

The `rlogin` service, which is available with the `rsh-server` package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set `disable` to `yes` in `/etc/xinetd.d/rlogin`. The `rlogin` socket can be disabled with the following command:

    $ sudo systemctl mask --now rlogin.socket

Rationale: | The rlogin service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_service_rlogin_disabled

Identifiers and References

References: 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'rlogin.service'
    "$SYSTEMCTL_EXEC" disable 'rlogin.service'
    "$SYSTEMCTL_EXEC" mask 'rlogin.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files rlogin.socket; then
        "$SYSTEMCTL_EXEC" stop 'rlogin.socket'
        "$SYSTEMCTL_EXEC" mask 'rlogin.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'rlogin.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service rlogin
      block:

      - name: Disable service rlogin
        block:

        - name: Disable service rlogin
          systemd:
            name: rlogin.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service rlogin' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rlogin_disabled

    - name: Unit Socket Exists - rlogin.socket
      command: systemctl -q list-unit-files rlogin.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rlogin_disabled

    - name: Disable socket rlogin
      systemd:
        name: rlogin.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("rlogin.socket",multiline=True)
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rlogin_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["rlogin"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_rlogin

    class disable_rlogin {
      service {'rlogin':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Disable rsh Service [ref]

The `rsh` service, which is available with the `rsh-server` package and runs as a service through xinetd or separately as a systemd socket, should be disabled. If using xinetd, set `disable` to `yes` in `/etc/xinetd.d/rsh`. The `rsh` socket can be disabled with the following command:

    $ sudo systemctl mask --now rsh.socket

Rationale: | The rsh service uses unencrypted network communications, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_service_rsh_disabled

Identifiers and References

References: 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, CCI-000068, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'rsh.service'
    "$SYSTEMCTL_EXEC" disable 'rsh.service'
    "$SYSTEMCTL_EXEC" mask 'rsh.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files rsh.socket; then
        "$SYSTEMCTL_EXEC" stop 'rsh.socket'
        "$SYSTEMCTL_EXEC" mask 'rsh.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'rsh.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service rsh
      block:

      - name: Disable service rsh
        block:

        - name: Disable service rsh
          systemd:
            name: rsh.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service rsh' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rsh_disabled

    - name: Unit Socket Exists - rsh.socket
      command: systemctl -q list-unit-files rsh.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rsh_disabled

    - name: Disable socket rsh
      systemd:
        name: rsh.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("rsh.socket",multiline=True)
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_rsh_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["rsh"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_rsh

    class disable_rsh {
      service {'rsh':
        enable => false,
        ensure => 'stopped',
      }
    }

#### Rule Remove Rsh Trust Files [ref]

The files `/etc/hosts.equiv` and `~/.rhosts` (in each user's home directory) list remote hosts and users that are trusted by the local system when using the rshd daemon. To remove these files, run the following command to delete them from any location:

    $ sudo rm /etc/hosts.equiv

    $ rm ~/.rhosts

Rationale: | This action is only meaningful if `.rhosts` support is permitted through PAM. Trust files are convenient, but when used in conjunction with the R-services, they can allow unauthenticated access to a system.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_no_rsh_trust_files

Identifiers and References

References: 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-001436, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q rsh-server; then

    find /root -xdev -type f -name ".rhosts" -exec rm -f {} \;
    find /home -maxdepth 2 -xdev -type f -name ".rhosts" -exec rm -f {} \;
    rm -f /etc/hosts.equiv

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - no_rsh_trust_files
      - restrict_strategy

    - name: Detect .rhosts files in users home directories
      find:
        paths:
        - /root
        - /home
        recurse: true
        patterns: .rhosts
        hidden: true
        file_type: file
      check_mode: false
      register: rhosts_locations
      when: '"rsh-server" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - no_rsh_trust_files
      - restrict_strategy

    - name: Remove .rhosts files
      file:
        path: '{{ item }}'
        state: absent
      with_items: '{{ rhosts_locations.files | map(attribute=''path'') | list }}'
      when:
      - '"rsh-server" in ansible_facts.packages'
      - rhosts_locations is success
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - no_rsh_trust_files
      - restrict_strategy

    - name: Remove /etc/hosts.equiv file
      file:
        path: /etc/hosts.equiv
        state: absent
      when: '"rsh-server" in ansible_facts.packages'
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - no_rsh_trust_files
      - restrict_strategy

Group Chat/Messaging Services Group contains 2 rules
[ref] The talk software makes it possible for users to send and receive messages across systems through a terminal session.

#### Rule Uninstall talk-server Package [ref]

The `talk-server` package can be removed with the following command:

     $ sudo yum erase talk-server

Rationale: | The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the `talk-server` package decreases the risk of the accidental (or intentional) activation of talk services.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_talk-server_removed
Identifiers and References | References: BP28(R1), 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove talk-server
    #	   from the system, and may remove any packages
    #	   that depend on talk-server. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "talk-server" ; then

        yum remove -y "talk-server"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=talk-server

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure talk-server is removed
      package:
        name: talk-server
        state: absent
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_talk-server_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_talk-server

    class remove_talk-server {
      package { 'talk-server':
        ensure => 'purged',
      }
    }

#### Rule Uninstall talk Package [ref]

The `talk` package contains the client program for the Internet talk protocol, which allows the user to chat with other users on different systems. Talk is a communication program which copies lines from one terminal to the terminal of another user. The `talk` package can be removed with the following command:

    $ sudo yum erase talk

Rationale: | The talk software presents a security risk as it uses unencrypted protocols for communications. Removing the `talk` package decreases the risk of the accidental (or intentional) activation of talk client program.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_package_talk_removed
Identifiers and References | References: BP28(R1), 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove talk
    #	   from the system, and may remove any packages
    #	   that depend on talk. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "talk" ; then

        yum remove -y "talk"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=talk

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure talk is removed
      package:
        name: talk
        state: absent
      tags:
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - package_talk_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_talk

    class remove_talk {
      package { 'talk':
        ensure => 'purged',
      }
    }

Group Telnet Group contains 3 rules
[ref] The telnet protocol does not provide confidentiality or integrity for information transmitted on the network. This includes authentication information such as passwords. Organizations which use telnet should be actively working to migrate to a more secure protocol.

#### Rule Uninstall telnet-server Package [ref]

The `telnet-server` package can be removed with the following command:

    $ sudo yum erase telnet-server

Rationale:

It is detrimental for operating systems to provide, or install by default, functionality exceeding requirements or mission objectives. These unnecessary capabilities are often overlooked and therefore may remain unsecure. They increase the risk to the platform by providing additional attack vectors.
The telnet service provides an unencrypted remote access service which does not provide for the confidentiality and integrity of user passwords or the remote session. If a privileged user were to login using this service, the privileged user password could be compromised.
Removing the `telnet-server` package decreases the risk of the telnet service's accidental (or intentional) activation.

Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_package_telnet-server_removed

Identifiers and References

References: BP28(R1), 11, 12, 14, 15, 3, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.05, DSS06.06, CCI-000381, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.2.1, A.6.2.2, A.9.1.2, CM-7(a), CM-7(b), CM-6(a), PR.AC-3, PR.IP-1, PR.PT-3, PR.PT-4, Req-2.2.2, 2.2.4, SRG-OS-000095-GPOS-00049, OL07-00-021710, SV-221763r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove telnet-server
    #	   from the system, and may remove any packages
    #	   that depend on telnet-server. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "telnet-server" ; then

        yum remove -y "telnet-server"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=telnet-server

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure telnet-server is removed
      package:
        name: telnet-server
        state: absent
      tags:
      - DISA-STIG-OL07-00-021710
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-2.2.2
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - package_telnet-server_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_telnet-server

    class remove_telnet-server {
      package { 'telnet-server':
        ensure => 'purged',
      }
    }

#### Rule Remove telnet Clients [ref]

The telnet client allows users to start connections to other systems via the telnet protocol.
Rationale: | The `telnet` protocol is insecure and unencrypted. The use of an unencrypted transmission medium could allow an unauthorized user to steal credentials. The `ssh` package provides an encrypted session and stronger security and is included in Oracle Linux 7.
Severity: | low
Rule ID: | xccdf_org.ssgproject.content_rule_package_telnet_removed
Identifiers and References | References: BP28(R1), 3.1.13, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), A.8.2.3, A.13.1.1, A.13.2.1, A.13.2.3, A.14.1.2, A.14.1.3, 2.2.4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # CAUTION: This remediation script will remove telnet
    #	   from the system, and may remove any packages
    #	   that depend on telnet. Execute this
    #	   remediation AFTER testing on a non-production
    #	   system!

    if rpm -q --quiet "telnet" ; then

        yum remove -y "telnet"

    fi

Remediation Anaconda snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    package --remove=telnet

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Ensure telnet is removed
      package:
        name: telnet
        state: absent
      tags:
      - NIST-800-171-3.1.13
      - PCI-DSSv4-2.2.4
      - disable_strategy
      - low_complexity
      - low_disruption
      - low_severity
      - no_reboot_needed
      - package_telnet_removed

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    include remove_telnet

    class remove_telnet {
      package { 'telnet':
        ensure => 'purged',
      }
    }

#### Rule Disable telnet Service [ref]

Make sure that the activation of the `telnet` service on system boot is disabled. The `telnet` socket can be disabled with the following command:

    $ sudo systemctl mask --now telnet.socket

Warning: If the system relies on `xinetd` to manage telnet sessions, ensure the telnet service is disabled by the following line: `disable = yes`. Note that the xinetd file for telnet is not created automatically, therefore it might have different names.

Rationale: | The telnet protocol uses unencrypted network communication, which means that data from the login session, including passwords and all other information transmitted during the session, can be stolen by eavesdroppers on the network. The telnet protocol is also subject to man-in-the-middle attacks.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_service_telnet_disabled

Identifiers and References

References: 1, 11, 12, 14, 15, 16, 3, 5, 8, 9, APO13.01, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, 3.1.13, 3.4.7, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-7(a), CM-7(b), CM-6(a), IA-5(1)(c), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-3, PR.PT-4

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'telnet.service'
    "$SYSTEMCTL_EXEC" disable 'telnet.service'
    "$SYSTEMCTL_EXEC" mask 'telnet.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files telnet.socket; then
        "$SYSTEMCTL_EXEC" stop 'telnet.socket'
        "$SYSTEMCTL_EXEC" mask 'telnet.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'telnet.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service telnet
      block:

      - name: Disable service telnet
        block:

        - name: Disable service telnet
          systemd:
            name: telnet.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service telnet' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_telnet_disabled

    - name: Unit Socket Exists - telnet.socket
      command: systemctl -q list-unit-files telnet.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_telnet_disabled

    - name: Disable socket telnet
      systemd:
        name: telnet.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("telnet.socket",multiline=True)
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.4.7
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-5(1)(c)
      - disable_strategy
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - service_telnet_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["telnet"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_telnet

    class disable_telnet {
      service {'telnet':
        enable => false,
        ensure => 'stopped',
      }
    }

Group Network Routing Group contains 1 group and 1 rule

[ref] A router is a very desirable target for a potential adversary because they fulfill a variety of infrastructure networking roles such as access to network segments, gateways to other networks, filtering, etc. Therefore, if one is required, the system acting as a router should be dedicated to that purpose alone and be stored in a physically secure location. The system's default routing software is Quagga, and provided in an RPM package of the same name.

Group Disable Quagga if Possible Group contains 1 rule
[ref] If Quagga was installed and activated, but the system does not need to act as a router, then it should be disabled and removed.

#### Rule Disable Quagga Service [ref]

The `zebra` service can be disabled with the following command:

    $ sudo systemctl mask --now zebra.service

Rationale: | Routing protocol daemons are typically used on routers to exchange network topology information with other routers. If routing daemons are used when not required, system network information may be unnecessarily transmitted across the network.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_zebra_disabled
Identifiers and References | References: 12, 15, 8, APO13.01, DSS05.02, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.13.1.1, A.13.2.1, A.14.1.3, CM-7(a), CM-7(b), CM-6(a), PR.PT-4, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" stop 'zebra.service'
    "$SYSTEMCTL_EXEC" disable 'zebra.service'
    "$SYSTEMCTL_EXEC" mask 'zebra.service'
    # Disable socket activation if we have a unit file for it
    if "$SYSTEMCTL_EXEC" -q list-unit-files zebra.socket; then
        "$SYSTEMCTL_EXEC" stop 'zebra.socket'
        "$SYSTEMCTL_EXEC" mask 'zebra.socket'
    fi
    # The service may not be running because it has been started and failed,
    # so let's reset the state so OVAL checks pass.
    # Service should be 'inactive', not 'failed' after reboot though.
    "$SYSTEMCTL_EXEC" reset-failed 'zebra.service' || true

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | disable

    - name: Block Disable service zebra
      block:

      - name: Disable service zebra
        block:

        - name: Disable service zebra
          systemd:
            name: zebra.service
            enabled: 'no'
            state: stopped
            masked: 'yes'
        rescue:

        - name: Intentionally ignored previous 'Disable service zebra' failure, service
            was already disabled
          meta: noop
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_zebra_disabled

    - name: Unit Socket Exists - zebra.socket
      command: systemctl -q list-unit-files zebra.socket
      register: socket_file_exists
      changed_when: false
      failed_when: socket_file_exists.rc not in [0, 1]
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_zebra_disabled

    - name: Disable socket zebra
      systemd:
        name: zebra.socket
        enabled: 'no'
        state: stopped
        masked: 'yes'
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - socket_file_exists.stdout_lines is search("zebra.socket",multiline=True)
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - disable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_zebra_disabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    disabled = ["zebra"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include disable_zebra

    class disable_zebra {
      service {'zebra':
        enable => false,
        ensure => 'stopped',
      }
    }

Group SSH Server Group contains 1 group and 21 rules

[ref] The SSH protocol is recommended for remote login and remote file transfer. SSH provides confidentiality and integrity for data exchanged between two systems, as well as server authentication, through the use of public key cryptography. The implementation included with the system is called OpenSSH, and more detailed documentation is available from its website, https://www.openssh.com. Its server program is called `sshd` and provided by the RPM package `openssh-server`.

Group Configure OpenSSH Server if Necessary Group contains 18 rules
[ref] If the system needs to act as an SSH server, then certain changes should be made to the OpenSSH daemon configuration file `/etc/ssh/sshd_config`. The following recommendations can be applied to this file. See the `sshd_config(5)` man page for more detailed information.

#### Rule Set SSH Client Alive Count Max to zero [ref]

The SSH server sends at most `ClientAliveCountMax` messages during a SSH session and waits for a response from the SSH client. The option `ClientAliveInterval` configures timeout after each `ClientAliveCountMax` message. If the SSH server does not receive a response from the client, then the connection is considered unresponsive and terminated. To ensure the SSH timeout occurs precisely when the `ClientAliveInterval` is set, set the `ClientAliveCountMax` to value of `0` in `/etc/ssh/sshd_config`:

Rationale: | This ensures a user login will be terminated as soon as the `ClientAliveInterval` is reached.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_set_keepalive_0

Identifiers and References

References: 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, OL07-00-040340, SV-221851r917860_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*ClientAliveCountMax\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "ClientAliveCountMax 0" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Set SSH Client Alive Count Max to zero
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveCountMax\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveCountMax\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveCountMax\s+
          line: ClientAliveCountMax 0
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-040340
      - NIST-800-171-3.1.11
      - NIST-800-53-AC-12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-2(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-10
      - PCI-DSS-Req-8.1.8
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_set_keepalive_0

#### Rule Set SSH Client Alive Interval [ref]

SSH allows administrators to set a network responsiveness timeout interval. After this interval has passed, the unresponsive client will be automatically logged out.
To set this timeout interval, edit the following line in `/etc/ssh/sshd_config` as follows:

    ClientAliveInterval 600

The timeout interval is given in seconds. For example, have a timeout of 10 minutes, set interval to 600.
If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made in `/etc/ssh/sshd_config`. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.
Warning: SSH disconnecting unresponsive clients will not have desired effect without also configuring ClientAliveCountMax in the SSH service configuration.
Warning: Following conditions may prevent the SSH session to time out:

- Remote processes on the remote machine generates output. As the output has to be transferred over the network to the client, the timeout is reset every time such transfer happens.
- Any `scp` or `sftp` activity by the same user to the host resets the timeout.

Rationale: | Terminating an idle ssh session within a short time period reduces the window of opportunity for unauthorized personnel to take control of a management session enabled on the console or console port that has been let unattended.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_set_idle_timeout

Identifiers and References

References: BP28(R29), 1, 12, 13, 14, 15, 16, 18, 3, 5, 7, 8, 5.5.6, APO13.01, BAI03.01, BAI03.02, BAI03.03, DSS01.03, DSS03.05, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.11, CCI-000879, CCI-001133, CCI-002361, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 6.2, A.12.4.1, A.12.4.3, A.14.1.1, A.14.2.1, A.14.2.5, A.18.1.4, A.6.1.2, A.6.1.5, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-004-6 R2.2.3, CIP-007-3 R5.1, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, CM-6(a), AC-17(a), AC-2(5), AC-12, AC-17(a), SC-10, CM-6(a), DE.CM-1, DE.CM-3, PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-2, Req-8.1.8, 8.2.8, SRG-OS-000126-GPOS-00066, SRG-OS-000163-GPOS-00072, SRG-OS-000279-GPOS-00109, SRG-OS-000395-GPOS-00175, OL07-00-040320, SV-221849r917857_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    sshd_idle_timeout_value='600'

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*ClientAliveInterval\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "ClientAliveInterval $sshd_idle_timeout_value" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value sshd_idle_timeout_value # promote to variable
      set_fact:
        sshd_idle_timeout_value: !!str 600
      tags:
        - always

    - name: Set SSH Client Alive Interval
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveInterval\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveInterval\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*ClientAliveInterval\s+
          line: ClientAliveInterval {{ sshd_idle_timeout_value }}
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-040320
      - NIST-800-171-3.1.11
      - NIST-800-53-AC-12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-2(5)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-10
      - PCI-DSS-Req-8.1.8
      - PCI-DSSv4-8.2.8
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_set_idle_timeout

#### Rule Disable Host-Based Authentication [ref]

SSH's cryptographic host-based authentication is more secure than `.rhosts` authentication. However, it is not recommended that hosts unilaterally trust one another, even within an organization.
The default SSH configuration disables host-based authentication. The appropriate configuration is used if no value is set for `HostbasedAuthentication`.
To explicitly disable host-based authentication, add or correct the following line in `/etc/ssh/sshd_config`:

    HostbasedAuthentication no

Rationale: | SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_disable_host_auth

Identifiers and References

References: 11, 12, 14, 15, 16, 18, 3, 5, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.03, DSS06.06, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-3, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.IP-1, PR.PT-3, FIA_UAU.1, 8.3.1, SRG-OS-000480-GPOS-00229, OL07-00-010470, SV-221697r877377_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*HostbasedAuthentication\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "HostbasedAuthentication no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable Host-Based Authentication
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*HostbasedAuthentication\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*HostbasedAuthentication\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*HostbasedAuthentication\s+
          line: HostbasedAuthentication no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-010470
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-3
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSSv4-8.3.1
      - disable_host_auth
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy

#### Rule Enable SSH Server firewalld Firewall Exception [ref]

If the SSH server is in use, inbound connections to SSH's port should be allowed to permit remote access through SSH. In more restrictive firewalld settings, the SSH port should be added to the proper firewalld zone in order to allow SSH remote access.
To configure `firewalld` to allow `ssh` access, run the following command(s):

    firewall-cmd --permanent --add-service=ssh

Then run the following command to load the newly created rule(s):

    firewall-cmd --reload

Warning: The remediation for this rule uses `firewall-cmd` and `nmcli` tools. Therefore, it will only be executed if `firewalld` and `NetworkManager` services are running. Otherwise, the remediation will be aborted and a informative message will be shown in the remediation report. These respective services will not be started in order to preserve any intentional change in network components related to firewall and network interfaces.
Warning: This rule also checks if the SSH port was modified by the administrator in the firewalld services definitions and is reflecting the expected port number. Although this is checked, fixing the custom ssh.xml file placed by the administrator at /etc/firewalld/services it is not in the scope of the remediation since there is no reliable way to manually change the respective file. If the default SSH port is modified, it is on the administrator responsibility to ensure the firewalld customizations in the service port level are properly configured.

Rationale: | If inbound SSH connections are expected, adding the SSH port to the proper firewalld zone will allow remote access through the SSH port.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_firewalld_sshd_port_enabled
Identifiers and References | References: 3.1.12, 1416, AC-17(a), CM-6(b), CM-7(a), CM-7(b), SRG-OS-000096-GPOS-00050

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if ! rpm -q --quiet "firewalld" ; then
        yum install -y "firewalld"
    fi
    if ! rpm -q --quiet "NetworkManager" ; then
        yum install -y "NetworkManager"
    fi
    firewalld_sshd_zone='public'

    if systemctl is-active NetworkManager && systemctl is-active firewalld; then
        # First make sure the SSH service is enabled in run-time for the proper zone.
        # This is to avoid connection issues when new interfaces are addeded to this zone.
        firewall-cmd --zone="$firewalld_sshd_zone" --add-service=ssh

        # This will collect all NetworkManager connections names
        readarray -t nm_connections < <(nmcli -f UUID,TYPE con | grep ethernet | awk '{ print $1 }')
        # If the connection is not yet assigned to a firewalld zone, assign it to the proper zone.
        # This will not change connections which are already assigned to any firewalld zone.
        for connection in "${nm_connections[@]}"; do
            current_zone=$(nmcli -f connection.zone connection show "$connection" | awk '{ print $2}')
            if [ $current_zone = "--" ]; then
                nmcli connection modify "$connection" connection.zone $firewalld_sshd_zone
            fi
        done
        systemctl restart NetworkManager

        # Active zones are zones with at least one interface assigned to it.
        # It is possible that traffic is comming by any active interface and consequently any
        # active zone. So, this make sure all active zones are permanently allowing SSH service.
        readarray -t firewalld_active_zones < <(firewall-cmd --get-active-zones | grep -v interfaces)
        for zone in "${firewalld_active_zones[@]}"; do
            firewall-cmd --permanent --zone="$zone" --add-service=ssh
        done
        firewall-cmd --reload
    else
        echo "
        firewalld and NetworkManager services are not active. Remediation aborted!
        This remediation could not be applied because it depends on firewalld and NetworkManager services running.
        The service is not started by this remediation in order to prevent connection issues."
        exit 1
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: XCCDF Value firewalld_sshd_zone # promote to variable
      set_fact:
        firewalld_sshd_zone: !!str public
      tags:
        - always

    - name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld and NetworkManager
        packages are installed
      ansible.builtin.package:
        name: '{{ item }}'
        state: present
      with_items:
      - firewalld
      - NetworkManager
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - firewalld_sshd_port_enabled
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Enable SSH Server firewalld Firewall Exception - Collect facts about system
        services
      ansible.builtin.service_facts: null
      register: result_services_states
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - firewalld_sshd_port_enabled
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Enable SSH Server firewalld Firewall Exception - Remediation is applicable
        if firewalld and NetworkManager services are running
      block:

      - name: Enable SSH Server firewalld Firewall Exception - Collect NetworkManager
          connections names
        ansible.builtin.shell:
          cmd: nmcli -f UUID,TYPE con | grep ethernet | awk '{ print $1 }'
        register: result_nmcli_cmd_connections_names
        changed_when: false

      - name: Enable SSH Server firewalld Firewall Exception - Collect NetworkManager
          connections zones
        ansible.builtin.shell:
          cmd: nmcli -f connection.zone connection show {{ item | trim }} | awk '{ print
            $2}'
        register: result_nmcli_cmd_connections_zones
        changed_when: false
        with_items:
        - '{{ result_nmcli_cmd_connections_names.stdout_lines }}'

      - name: Enable SSH Server firewalld Firewall Exception - Ensure NetworkManager connections
          are assigned to a firewalld zone
        ansible.builtin.command:
          cmd: nmcli connection modify {{ item.0 }} connection.zone {{ firewalld_sshd_zone
            }}
        register: result_nmcli_cmd_connections_assignment
        with_together:
        - '{{ result_nmcli_cmd_connections_names.stdout_lines }}'
        - '{{ result_nmcli_cmd_connections_zones.results }}'
        when:
        - item.1.stdout == '--'

      - name: Enable SSH Server firewalld Firewall Exception - Ensure NetworkManager connections
          changes are applied
        ansible.builtin.service:
          name: NetworkManager
          state: restarted
        when:
        - result_nmcli_cmd_connections_assignment is changed

      - name: Enable SSH Server firewalld Firewall Exception - Collect firewalld active
          zones
        ansible.builtin.shell:
          cmd: firewall-cmd --get-active-zones | grep -v interfaces
        register: result_firewall_cmd_zones_names
        changed_when: false

      - name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld zones
          allow SSH
        ansible.builtin.command:
          cmd: firewall-cmd --permanent --zone={{ item }} --add-service=ssh
        register: result_nmcli_cmd_connections_assignment
        changed_when:
        - '''ALREADY_ENABLED'' not in result_nmcli_cmd_connections_assignment.stderr'
        with_items:
        - '{{ result_firewall_cmd_zones_names.stdout_lines }}'

      - name: Enable SSH Server firewalld Firewall Exception - Ensure firewalld changes
          are applied
        ansible.builtin.service:
          name: firewalld
          state: reloaded
        when:
        - result_nmcli_cmd_connections_assignment is changed
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_facts.services['firewalld.service'].state == 'running'
      - ansible_facts.services['NetworkManager.service'].state == 'running'
      tags:
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - firewalld_sshd_port_enabled
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Enable SSH Server firewalld Firewall Exception - Informative message based
        on services states
      ansible.builtin.assert:
        that:
        - ansible_facts.services['firewalld.service'].state == 'running'
        - ansible_facts.services['NetworkManager.service'].state == 'running'
        fail_msg:
        - firewalld and NetworkManager services are not active. Remediation aborted!
        - This remediation could not be applied because it depends on firewalld and NetworkManager
          services running.
        - The service is not started by this remediation in order to prevent connection
          issues.
        success_msg:
        - Enable SSH Server firewalld Firewall Exception remediation successfully executed
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(b)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - configure_strategy
      - firewalld_sshd_port_enabled
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

#### Rule Allow Only SSH Protocol 2 [ref]

Only SSH protocol version 2 connections should be permitted. The default setting in `/etc/ssh/sshd_config` is correct, and can be verified by ensuring that the following line appears:

    Protocol 2

Warning: As of `openssh-server` version `7.4` and above, the only protocol supported is version 2, and line

    Protocol 2

in `/etc/ssh/sshd_config` is not necessary.

Rationale: | SSH protocol version 1 is an insecure implementation of the SSH protocol and has many well-known vulnerability exploits. Exploits of the SSH daemon could provide immediate root access to the system.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_allow_only_protocol2

Identifiers and References

References: NT007(R1), 1, 12, 15, 16, 5, 8, 5.5.6, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, 3.1.13, 3.5.4, CCI-000197, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, 0487, 1449, 1506, A.11.2.6, A.13.1.1, A.13.2.1, A.14.1.3, A.18.1.4, A.6.2.1, A.6.2.2, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CIP-003-8 R4.2, CIP-007-3 R5.1, CIP-007-3 R7.1, CM-6(a), AC-17(a), AC-17(2), IA-5(1)(c), SC-13, MA-4(6), PR.AC-1, PR.AC-3, PR.AC-6, PR.AC-7, PR.PT-4, SRG-OS-000074-GPOS-00042, SRG-OS-000480-GPOS-00227, OL07-00-040390, SV-221856r877396_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^Protocol")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "2"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^Protocol\\>" "/etc/ssh/sshd_config"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^Protocol\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
    else
        if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Allow Only SSH Protocol 2
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Protocol\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Protocol\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Protocol\s+
          line: Protocol 2
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-040390
      - NIST-800-171-3.1.13
      - NIST-800-171-3.5.4
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-MA-4(6)
      - NIST-800-53-SC-13
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy
      - sshd_allow_only_protocol2

#### Rule Disable Compression Or Set Compression to delayed [ref]

Compression is useful for slow network connections over long distances but can cause performance issues on local LANs. If use of compression is required, it should be enabled only after a user has authenticated; otherwise, it should be disabled. To disable compression or delay compression until after a user has successfully authenticated, add or correct the following line in the `/etc/ssh/sshd_config` file:

    Compression no

Rationale: | If compression is allowed in an SSH connection prior to authentication, vulnerabilities in the compression software could result in compromise of the system from an unauthenticated connection, potentially with root privileges.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_compression

Identifiers and References

References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, SRG-OS-000480-GPOS-00227, OL07-00-040470, SV-221864r880591_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ] && { grep -qP "^ID=[\"']?ol[\"']?$" "/etc/os-release" && { real="$(grep -P "^VERSION_ID=[\"']?[\w.]+[\"']?$" /etc/os-release | sed "s/^VERSION_ID=[\"']\?\([^\"']\+\)[\"']\?$/\1/")"; expected="7.4"; [[ "$real" != "$expected" ]] && printf "%s\n%s" "$real" "$expected" | sort -VC; }; }; then

    var_sshd_disable_compression='no'

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*Compression\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "Compression $var_sshd_disable_compression" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_sshd_disable_compression # promote to variable
      set_fact:
        var_sshd_disable_compression: !!str no
      tags:
        - always

    - name: Disable Compression Or Set Compression to delayed
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Compression\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Compression\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Compression\s+
          line: Compression {{ var_sshd_disable_compression }}
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when:
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - ansible_distribution == 'OracleLinux' and ansible_distribution_version is version('7.4',
        '<')
      tags:
      - DISA-STIG-OL07-00-040470
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_compression

#### Rule Disable SSH Access via Empty Passwords [ref]

Disallow SSH login with empty passwords. The default SSH configuration disables logins with empty passwords. The appropriate configuration is used if no value is set for `PermitEmptyPasswords`.
To explicitly disallow SSH login from accounts with empty passwords, add or correct the following line in `/etc/ssh/sshd_config`:

    PermitEmptyPasswords no

Any accounts with empty passwords should be disabled immediately, and PAM configuration should prevent users from being able to assign themselves empty passwords.

Rationale: | Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_empty_passwords

Identifiers and References

References: NT007(R17), 11, 12, 13, 14, 15, 16, 18, 3, 5, 9, 5.5.6, APO01.06, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS06.02, DSS06.03, DSS06.06, 3.1.1, 3.1.5, CCI-000366, CCI-000766, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.12.1.2, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.AC-4, PR.AC-6, PR.DS-5, PR.IP-1, PR.PT-3, FIA_UAU.1, Req-2.2.4, 2.2.6, SRG-OS-000106-GPOS-00053, SRG-OS-000480-GPOS-00229, SRG-OS-000480-GPOS-00227, OL07-00-010300, SV-221688r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*PermitEmptyPasswords\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "PermitEmptyPasswords no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable SSH Access via Empty Passwords
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitEmptyPasswords\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitEmptyPasswords\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitEmptyPasswords\s+
          line: PermitEmptyPasswords no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-010300
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_empty_passwords

#### Rule Disable GSSAPI Authentication [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like GSSAPI.
The default SSH configuration disallows authentications based on GSSAPI. The appropriate configuration is used if no value is set for `GSSAPIAuthentication`.
To explicitly disable GSSAPI authentication, add or correct the following line in `/etc/ssh/sshd_config`:

    GSSAPIAuthentication no

Rationale: | GSSAPI authentication is used to provide additional authentication mechanisms to applications. Allowing GSSAPI authentication through SSH exposes the system's GSSAPI to remote hosts, increasing the attack surface of the system.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_gssapi_auth

Identifiers and References

References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, 0418, 1055, 1402, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, CM-7(a), CM-7(b), CM-6(a), AC-17(a), PR.IP-1, FTP_ITC_EXT.1, FCS_SSH_EXT.1.2, SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227, OL07-00-040430, SV-221860r853722_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*GSSAPIAuthentication\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "GSSAPIAuthentication no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable GSSAPI Authentication
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*GSSAPIAuthentication\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*GSSAPIAuthentication\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*GSSAPIAuthentication\s+
          line: GSSAPIAuthentication no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040430
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_gssapi_auth

#### Rule Disable Kerberos Authentication [ref]

Unless needed, SSH should not permit extraneous or unnecessary authentication mechanisms like Kerberos.
The default SSH configuration disallows authentication validation through Kerberos. The appropriate configuration is used if no value is set for `KerberosAuthentication`.
To explicitly disable Kerberos authentication, add or correct the following line in `/etc/ssh/sshd_config`:

    KerberosAuthentication no

Rationale: | Kerberos authentication for SSH is often implemented using GSSAPI. If Kerberos is enabled through SSH, the SSH daemon provides a means of access to the system's Kerberos implementation. Configuring these settings for the SSH daemon provides additional assurance that remote logon via SSH will not use unused methods of authentication, even in the event of misconfiguration elsewhere.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_kerb_auth

Identifiers and References

References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000318, CCI-000368, CCI-001812, CCI-001813, CCI-001814, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FTP_ITC_EXT.1, FCS_SSH_EXT.1.2, SRG-OS-000364-GPOS-00151, SRG-OS-000480-GPOS-00227, OL07-00-040440, SV-221861r853723_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*KerberosAuthentication\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "KerberosAuthentication no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable Kerberos Authentication
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*KerberosAuthentication\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*KerberosAuthentication\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*KerberosAuthentication\s+
          line: KerberosAuthentication no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040440
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_kerb_auth

#### Rule Disable SSH Support for Rhosts RSA Authentication [ref]

SSH can allow authentication through the obsolete rsh command through the use of the authenticating user's SSH keys. This should be disabled.
To ensure this behavior is disabled, add or correct the following line in `/etc/ssh/sshd_config`:

    RhostsRSAAuthentication no

Warning: As of `openssh-server` version `7.4` and above, the `RhostsRSAAuthentication` option has been deprecated, and the line

    RhostsRSAAuthentication no

in `/etc/ssh/sshd_config` is not necessary.

Rationale: | Configuring this setting for the SSH daemon provides additional assurance that remote login via SSH will require a password, even in the event of misconfiguration elsewhere.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_rhosts_rsa

Identifiers and References

References: 11, 3, 9, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, FIA_UAU.1, SRG-OS-000480-GPOS-00227, OL07-00-040330, SV-221850r603260_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^RhostsRSAAuthentication")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "no"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^RhostsRSAAuthentication\\>" "/etc/ssh/sshd_config"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^RhostsRSAAuthentication\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
    else
        if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable SSH Support for Rhosts RSA Authentication
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*RhostsRSAAuthentication\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*RhostsRSAAuthentication\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*RhostsRSAAuthentication\s+
          line: RhostsRSAAuthentication no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040330
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_rhosts_rsa

#### Rule Disable SSH Root Login [ref]

The root user should never be allowed to login to a system directly over a network. To disable root login via SSH, add or correct the following line in `/etc/ssh/sshd_config`:

    PermitRootLogin no

Rationale: | Even though the communications channel may be encrypted, an additional layer of security is gained by extending the policy of not logging directly on as root. In addition, logging in with a user-specific account provides individual accountability of actions performed on the system and also helps to minimize direct attack attempts on root's password.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_disable_root_login

Identifiers and References

References: BP28(R19), NT007(R21), 1, 11, 12, 13, 14, 15, 16, 18, 3, 5, 5.5.6, APO01.06, DSS05.02, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.02, DSS06.03, DSS06.06, DSS06.10, 3.1.1, 3.1.5, CCI-000366, CCI-000770, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.18.1.4, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.2.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CIP-007-3 R5.2, CIP-007-3 R5.3.1, CIP-007-3 R5.3.2, CIP-007-3 R5.3.3, AC-6(2), AC-17(a), IA-2, IA-2(5), CM-7(a), CM-7(b), CM-6(a), PR.AC-1, PR.AC-4, PR.AC-6, PR.AC-7, PR.DS-5, PR.PT-3, FAU_GEN.1, Req-2.2.4, 2.2.6, SRG-OS-000109-GPOS-00056, SRG-OS-000480-GPOS-00227, SRG-APP-000148-CTR-000335, SRG-APP-000190-CTR-000500, OL07-00-040370, SV-221854r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*PermitRootLogin\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "PermitRootLogin no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Disable SSH Root Login
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitRootLogin\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitRootLogin\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitRootLogin\s+
          line: PermitRootLogin no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-040370
      - NIST-800-171-3.1.1
      - NIST-800-171-3.1.5
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(2)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - NIST-800-53-IA-2
      - NIST-800-53-IA-2(5)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_disable_root_login

#### Rule Do Not Allow SSH Environment Options [ref]

Ensure that users are not able to override environment variables of the SSH daemon.
The default SSH configuration disables environment processing. The appropriate configuration is used if no value is set for `PermitUserEnvironment`.
To explicitly disable Environment options, add or correct the following `/etc/ssh/sshd_config`:

    PermitUserEnvironment no

Rationale: | SSH environment options potentially allow users to bypass access restriction in some configurations.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_do_not_permit_user_env

Identifiers and References

References: 11, 3, 9, 5.5.6, BAI10.01, BAI10.02, BAI10.03, BAI10.05, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.4.3.2, 4.3.4.3.3, SR 7.6, A.12.1.2, A.12.5.1, A.12.6.2, A.14.2.2, A.14.2.3, A.14.2.4, AC-17(a), CM-7(a), CM-7(b), CM-6(a), PR.IP-1, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00229, OL07-00-010460, SV-221696r877377_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*PermitUserEnvironment\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "PermitUserEnvironment no" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Do Not Allow SSH Environment Options
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitUserEnvironment\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitUserEnvironment\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*PermitUserEnvironment\s+
          line: PermitUserEnvironment no
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-010460
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-CM-7(a)
      - NIST-800-53-CM-7(b)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_do_not_permit_user_env

#### Rule Enable Use of Strict Mode Checking [ref]

SSHs `StrictModes` option checks file and ownership permissions in the user's home directory `.ssh` folder before accepting login. If world- writable permissions are found, logon is rejected.
The default SSH configuration has `StrictModes` enabled. The appropriate configuration is used if no value is set for `StrictModes`.
To explicitly enable `StrictModes` in SSH, add or correct the following line in `/etc/ssh/sshd_config`:

    StrictModes yes

Rationale: | If other users have access to modify user-specific SSH configuration files, they may be able to log into the system as another user.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_enable_strictmodes

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-6, AC-17(a), CM-6(a), PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-040450, SV-221862r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*StrictModes\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "StrictModes yes" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Enable Use of Strict Mode Checking
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*StrictModes\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*StrictModes\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*StrictModes\s+
          line: StrictModes yes
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040450
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6
      - NIST-800-53-CM-6(a)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_enable_strictmodes

#### Rule Enable SSH Warning Banner [ref]

To enable the warning banner and ensure it is consistent across the system, add or correct the following line in `/etc/ssh/sshd_config`:

    Banner /etc/issue

Another section contains information on how to create an appropriate system-wide warning banner.

Rationale: | The warning message reinforces policy awareness during the logon process and facilitates possible legal action against attackers. Alternatively, systems whose ownership should not be obvious should ensure usage of a banner that does not provide easy attribution.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_enable_warning_banner

Identifiers and References

References: 1, 12, 15, 16, 5.5.6, DSS05.04, DSS05.10, DSS06.10, 3.1.9, CCI-000048, CCI-000050, CCI-001384, CCI-001385, CCI-001386, CCI-001387, CCI-001388, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, SR 1.1, SR 1.10, SR 1.2, SR 1.5, SR 1.7, SR 1.8, SR 1.9, A.18.1.4, A.9.2.1, A.9.2.4, A.9.3.1, A.9.4.2, A.9.4.3, AC-8(a), AC-8(c), AC-17(a), CM-6(a), PR.AC-7, FTA_TAB.1, Req-2.2.4, SRG-OS-000023-GPOS-00006, SRG-OS-000228-GPOS-00088, OL07-00-040170, SV-221842r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*Banner\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "Banner /etc/issue" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Enable SSH Warning Banner
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Banner\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Banner\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Banner\s+
          line: Banner /etc/issue
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - DISA-STIG-OL07-00-040170
      - NIST-800-171-3.1.9
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-8(a)
      - NIST-800-53-AC-8(c)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_enable_warning_banner

#### Rule Enable Encrypted X11 Forwarding [ref]

By default, remote X11 connections are not encrypted when initiated by users. SSH has the capability to encrypt remote X11 connections when SSH's `X11Forwarding` option is enabled.
To enable X11 Forwarding, add or correct the following line in `/etc/ssh/sshd_config`:

    X11Forwarding yes

Rationale: | Non-encrypted X displays allow an attacker to capture keystrokes and to execute commands remotely.
Severity: | high
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_enable_x11_forwarding

Identifiers and References

References: 1, 11, 12, 13, 15, 16, 18, 20, 3, 4, 6, 9, BAI03.08, BAI07.04, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS03.01, 3.1.13, CCI-000366, 4.3.4.3.2, 4.3.4.3.3, 4.4.3.3, SR 7.6, A.12.1.1, A.12.1.2, A.12.1.4, A.12.5.1, A.12.6.2, A.13.1.1, A.13.1.2, A.14.2.2, A.14.2.3, A.14.2.4, CIP-007-3 R7.1, CM-6(a), AC-17(a), AC-17(2), DE.AE-1, PR.DS-7, PR.IP-1, SRG-OS-000480-GPOS-00227

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*X11Forwarding\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "X11Forwarding yes" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: Enable Encrypted X11 Forwarding
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*X11Forwarding\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*X11Forwarding\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*X11Forwarding\s+
          line: X11Forwarding yes
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - high_severity
      - low_complexity
      - low_disruption
      - no_reboot_needed
      - restrict_strategy
      - sshd_enable_x11_forwarding

#### Rule Use Only FIPS 140-2 Validated Ciphers [ref]

Limit the ciphers to those algorithms which are FIPS-approved. Counter (CTR) mode is also preferred over cipher-block chaining (CBC) mode. The following line in `/etc/ssh/sshd_config` demonstrates use of FIPS-approved ciphers:

    Ciphers aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc

The man page `sshd_config(5)` contains a list of supported ciphers.
Only the following ciphers are FIPS 140-2 certified on Oracle Linux 7:
- aes128-ctr
- aes192-ctr
- aes256-ctr
- aes128-cbc
- aes192-cbc
- aes256-cbc
- 3des-cbc
- rijndael-cbc@lysator.liu.se
Any combination of the above ciphers will pass this check. Official FIPS 140-2 paperwork for Oracle Linux 7 can be found at https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3028.pdf The rule is parametrized to use the following ciphers: `aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se`.
Warning: The system needs to be rebooted for these changes to take effect.
Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale:

Unapproved mechanisms that are used for authentication to the cryptographic module are not verified and therefore cannot be relied upon to provide confidentiality or integrity, and system data may be compromised.
Operating systems utilizing encryption are required to use FIPS-compliant mechanisms for authenticating to cryptographic modules.
FIPS 140-2 is the current standard for validating that mechanisms used to access cryptographic modules utilize authentication that meets industry and government requirements. For government systems, this allows Security Levels 1, 2, 3, or 4 for use on Oracle Linux 7.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_use_approved_ciphers

Identifiers and References

References: 1, 11, 12, 14, 15, 16, 18, 3, 5, 6, 8, 9, 5.5.6, APO11.04, APO13.01, BAI03.05, BAI10.01, BAI10.02, BAI10.03, BAI10.05, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.06, DSS06.10, MEA02.01, 3.1.13, 3.13.11, 3.13.8, CCI-000068, CCI-000366, CCI-000803, CCI-000877, CCI-002890, CCI-003123, 164.308(b)(1), 164.308(b)(2), 164.312(e)(1), 164.312(e)(2)(i), 164.312(e)(2)(ii), 164.314(b)(2)(i), 4.3.3.2.2, 4.3.3.3.9, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.5.3, 4.3.3.5.4, 4.3.3.5.5, 4.3.3.5.6, 4.3.3.5.7, 4.3.3.5.8, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.1, 4.3.3.7.2, 4.3.3.7.3, 4.3.3.7.4, 4.3.4.3.2, 4.3.4.3.3, 4.3.4.4.7, 4.4.2.1, 4.4.2.2, 4.4.2.4, SR 1.1, SR 1.10, SR 1.11, SR 1.12, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.6, SR 1.7, SR 1.8, SR 1.9, SR 2.1, SR 2.10, SR 2.11, SR 2.12, SR 2.2, SR 2.3, SR 2.4, SR 2.5, SR 2.6, SR 2.7, SR 2.8, SR 2.9, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.11.2.6, A.12.1.2, A.12.4.1, A.12.4.2, A.12.4.3, A.12.4.4, A.12.5.1, A.12.6.2, A.12.7.1, A.13.1.1, A.13.2.1, A.14.1.3, A.14.2.2, A.14.2.3, A.14.2.4, A.18.1.4, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-17(a), AC-17(2), SC-13, MA-4(6), IA-5(1)(c), SC-12(2), SC-12(3), PR.AC-1, PR.AC-3, PR.AC-4, PR.AC-6, PR.AC-7, PR.IP-1, PR.PT-1, PR.PT-3, PR.PT-4, 2.2.7, SRG-OS-000033-GPOS-00014, SRG-OS-000120-GPOS-00061, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000393-GPOS-00173, SRG-OS-000394-GPOS-00174

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    sshd_approved_ciphers='aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^Ciphers")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "$sshd_approved_ciphers"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^Ciphers\\>" "/etc/ssh/sshd_config"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^Ciphers\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
    else
        if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value sshd_approved_ciphers # promote to variable
      set_fact:
        sshd_approved_ciphers: !!str aes128-ctr,aes192-ctr,aes256-ctr,aes128-cbc,3des-cbc,aes192-cbc,aes256-cbc,rijndael-cbc@lysator.liu.se
      tags:
        - always

    - name: Use Only FIPS 140-2 Validated Ciphers
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Ciphers\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Ciphers\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*Ciphers\s+
          line: Ciphers {{ sshd_approved_ciphers }}
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - CJIS-5.5.6
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(1)(c)
      - NIST-800-53-MA-4(6)
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - PCI-DSSv4-2.2.7
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_use_approved_ciphers

#### Rule Use Only FIPS 140-2 Validated MACs [ref]

Limit the MACs to those hash algorithms which are FIPS-approved. The following line in `/etc/ssh/sshd_config` demonstrates use of FIPS-approved MACs:

    MACs hmac-sha2-512,hmac-sha2-256,hmac-sha1

The man page `sshd_config(5)` contains a list of supported MACs.
Only the following message authentication codes are FIPS 140-2 certified on Oracle Linux 7:
- hmac-sha1
- hmac-sha2-256
- hmac-sha2-512
- hmac-sha1-etm@openssh.com
- hmac-sha2-256-etm@openssh.com
- hmac-sha2-512-etm@openssh.com
Any combination of the above MACs will pass this check. Official FIPS 140-2 paperwork for Oracle Linux 7 can be found at https://csrc.nist.gov/CSRC/media/projects/cryptographic-module-validation-program/documents/security-policies/140sp3028.pdf The rule is parametrized to use the following MACs: `hmac-sha2-512,hmac-sha2-256,hmac-sha1,hmac-sha1-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com`.
Warning: The system needs to be rebooted for these changes to take effect.
Warning: System Crypto Modules must be provided by a vendor that undergoes FIPS-140 certifications. FIPS-140 is applicable to all Federal agencies that use cryptographic-based security systems to protect sensitive information in computer and telecommunication systems (including voice systems) as defined in Section 5131 of the Information Technology Management Reform Act of 1996, Public Law 104-106. This standard shall be used in designing and implementing cryptographic modules that Federal departments and agencies operate or are operated for them under contract. See https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.140-2.pdf To meet this, the system has to have cryptographic software provided by a vendor that has undergone this certification. This means providing documentation, test results, design information, and independent third party review by an accredited lab. While open source software is capable of meeting this, it does not meet FIPS-140 unless the vendor submits to this process.

Rationale: | DoD Information Systems are required to use FIPS-approved cryptographic hash functions. The only SSHv2 hash algorithms meeting this requirement is SHA2.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_use_approved_macs

Identifiers and References

References: 1, 12, 13, 15, 16, 5, 8, APO01.06, APO13.01, DSS01.04, DSS05.02, DSS05.03, DSS05.04, DSS05.07, DSS06.02, DSS06.03, 3.1.13, 3.13.11, 3.13.8, CCI-000068, CCI-000803, CCI-000877, CCI-001453, CCI-003123, 164.308(b)(1), 164.308(b)(2), 164.312(e)(1), 164.312(e)(2)(i), 164.312(e)(2)(ii), 164.314(b)(2)(i), 4.3.3.5.1, 4.3.3.6.6, SR 1.1, SR 1.13, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.6, SR 3.1, SR 3.5, SR 3.8, SR 4.1, SR 4.3, SR 5.1, SR 5.2, SR 5.3, SR 7.1, SR 7.6, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.11.2.6, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.6.2.1, A.6.2.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.1, A.9.4.2, A.9.4.3, A.9.4.4, A.9.4.5, CM-6(a), AC-17(a), AC-17(2), SC-13, MA-4(6), SC-12(2), SC-12(3), PR.AC-1, PR.AC-3, PR.DS-5, PR.PT-4, 2.2.7, SRG-OS-000125-GPOS-00065, SRG-OS-000250-GPOS-00093, SRG-OS-000394-GPOS-00174

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    sshd_approved_macs='hmac-sha2-512,hmac-sha2-256,hmac-sha1,hmac-sha1-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com'

    # Strip any search characters in the key arg so that the key can be replaced without
    # adding any search characters to the config file.
    stripped_key=$(sed 's/[\^=\$,;+]*//g' <<< "^MACs")

    # shellcheck disable=SC2059
    printf -v formatted_output "%s %s" "$stripped_key" "$sshd_approved_macs"

    # If the key exists, change it. Otherwise, add it to the config_file.
    # We search for the key string followed by a word boundary (matched by \>),
    # so if we search for 'setting', 'setting2' won't match.
    if LC_ALL=C grep -q -m 1 -i -e "^MACs\\>" "/etc/ssh/sshd_config"; then
        escaped_formatted_output=$(sed -e 's|/|\\/|g' <<< "$formatted_output")
        LC_ALL=C sed -i --follow-symlinks "s/^MACs\\>.*/$escaped_formatted_output/gi" "/etc/ssh/sshd_config"
    else
        if [[ -s "/etc/ssh/sshd_config" ]] && [[ -n "$(tail -c 1 -- "/etc/ssh/sshd_config" || true)" ]]; then
            LC_ALL=C sed -i --follow-symlinks '$a'\\ "/etc/ssh/sshd_config"
        fi
        printf '%s\n' "$formatted_output" >> "/etc/ssh/sshd_config"
    fi

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value sshd_approved_macs # promote to variable
      set_fact:
        sshd_approved_macs: !!str hmac-sha2-512,hmac-sha2-256,hmac-sha1,hmac-sha1-etm@openssh.com,hmac-sha2-256-etm@openssh.com,hmac-sha2-512-etm@openssh.com
      tags:
        - always

    - name: Use Only FIPS 140-2 Validated MACs
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*MACs\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*MACs\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*MACs\s+
          line: MACs {{ sshd_approved_macs }}
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.11
      - NIST-800-171-3.13.8
      - NIST-800-53-AC-17(2)
      - NIST-800-53-AC-17(a)
      - NIST-800-53-CM-6(a)
      - NIST-800-53-MA-4(6)
      - NIST-800-53-SC-12(2)
      - NIST-800-53-SC-12(3)
      - NIST-800-53-SC-13
      - PCI-DSSv4-2.2.7
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_use_approved_macs

#### Rule Enable Use of Privilege Separation [ref]

When enabled, SSH will create an unprivileged child process that has the privilege of the authenticated user. To enable privilege separation in SSH, add or correct the following line in the `/etc/ssh/sshd_config` file:

    UsePrivilegeSeparation sandbox

Rationale: | SSH daemon privilege separation causes the SSH process to drop root privileges when not needed which would decrease the impact of software vulnerabilities in the unprivileged section.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sshd_use_priv_separation

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.12, CCI-000366, 164.308(a)(4)(i), 164.308(b)(1), 164.308(b)(3), 164.310(b), 164.312(e)(1), 164.312(e)(2)(ii), 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, CM-6(a), AC-17(a), AC-6, PR.AC-4, PR.DS-5, SRG-OS-000480-GPOS-00227, OL07-00-040460, SV-221863r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    var_sshd_priv_separation='sandbox'

    if [ -e "/etc/ssh/sshd_config" ] ; then

        LC_ALL=C sed -i "/^\s*UsePrivilegeSeparation\s\+/Id" "/etc/ssh/sshd_config"
    else
        touch "/etc/ssh/sshd_config"
    fi
    # make sure file has newline at the end
    sed -i -e '$a\' "/etc/ssh/sshd_config"

    cp "/etc/ssh/sshd_config" "/etc/ssh/sshd_config.bak"
    # Insert at the beginning of the file
    printf '%s\n' "UsePrivilegeSeparation $var_sshd_priv_separation" > "/etc/ssh/sshd_config"
    cat "/etc/ssh/sshd_config.bak" >> "/etc/ssh/sshd_config"
    # Clean up after ourselves.
    rm "/etc/ssh/sshd_config.bak"

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | restrict

    - name: XCCDF Value var_sshd_priv_separation # promote to variable
      set_fact:
        var_sshd_priv_separation: !!str sandbox
      tags:
        - always

    - name: Enable Use of Privilege Separation
      block:

      - name: Check for duplicate values
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*UsePrivilegeSeparation\s+
          state: absent
        check_mode: true
        changed_when: false
        register: dupes

      - name: Deduplicate values from /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*UsePrivilegeSeparation\s+
          state: absent
        when: dupes.found is defined and dupes.found > 1

      - name: Insert correct line to /etc/ssh/sshd_config
        lineinfile:
          path: /etc/ssh/sshd_config
          create: true
          regexp: (?i)^\s*UsePrivilegeSeparation\s+
          line: UsePrivilegeSeparation {{ var_sshd_priv_separation }}
          state: present
          insertbefore: BOF
          validate: /usr/sbin/sshd -t -f %s
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040460
      - NIST-800-171-3.1.12
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6
      - NIST-800-53-CM-6(a)
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - restrict_strategy
      - sshd_use_priv_separation

#### Rule Enable the OpenSSH Service [ref]

The SSH server service, sshd, is commonly needed. The `sshd` service can be enabled with the following command:

    $ sudo systemctl enable sshd.service

Rationale:

Without protection of the transmitted information, confidentiality, and integrity may be compromised because unprotected communications can be intercepted and either read or altered.
This checklist item applies to both internal and external networks and all types of information system components from which information can be transmitted (e.g., servers, mobile devices, notebook computers, printers, copiers, scanners, etc). Communication paths outside the physical protection of a controlled boundary are exposed to the possibility of interception and modification.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_service_sshd_enabled

Identifiers and References

References: 13, 14, APO01.06, DSS05.02, DSS05.04, DSS05.07, DSS06.02, DSS06.06, 3.1.13, 3.5.4, 3.13.8, CCI-002418, CCI-002420, CCI-002421, CCI-002422, SR 3.1, SR 3.8, SR 4.1, SR 4.2, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CM-6(a), SC-8, SC-8(1), SC-8(2), SC-8(3), SC-8(4), PR.DS-2, PR.DS-5, SRG-OS-000423-GPOS-00187, SRG-OS-000424-GPOS-00188, SRG-OS-000425-GPOS-00189, SRG-OS-000426-GPOS-00190, OL07-00-040310, SV-221848r916422_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    SYSTEMCTL_EXEC='/usr/bin/systemctl'
    "$SYSTEMCTL_EXEC" unmask 'sshd.service'
    "$SYSTEMCTL_EXEC" start 'sshd.service'
    "$SYSTEMCTL_EXEC" enable 'sshd.service'

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    - name: Enable service sshd
      block:

      - name: Gather the package facts
        package_facts:
          manager: auto

      - name: Enable service sshd
        systemd:
          name: sshd
          enabled: 'yes'
          state: started
          masked: 'no'
        when:
        - '"openssh-server" in ansible_facts.packages'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040310
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.8
      - NIST-800-171-3.5.4
      - NIST-800-53-CM-6(a)
      - NIST-800-53-SC-8
      - NIST-800-53-SC-8(1)
      - NIST-800-53-SC-8(2)
      - NIST-800-53-SC-8(3)
      - NIST-800-53-SC-8(4)
      - enable_strategy
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed
      - service_sshd_enabled

Remediation OSBuild Blueprint snippet ⇲

    [customizations.services]
    enabled = ["sshd"]

Remediation Puppet snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | enable

    include enable_sshd

    class enable_sshd {
      service {'sshd':
        enable => true,
        ensure => 'running',
      }
    }

#### Rule Verify Permissions on SSH Server Private *_key Key Files [ref]

SSH server private keys - files that match the `/etc/ssh/*_key` glob, have to have restricted permissions. If those files are owned by the `root` user and the `root` group, they have to have the `0600` permission or stricter. If they are owned by the `root` user, but by a dedicated group `ssh_keys`, they can have the `0640` permission or stricter.
Rationale: | If an unauthorized user obtains the private SSH host key file, the host could be impersonated.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_sshd_private_key

Identifiers and References

References: BP28(R36), 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-040420, SV-221859r880579_rule

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    for keyfile in /etc/ssh/*_key; do
        test -f "$keyfile" || continue
        if test root:root = "$(stat -c "%U:%G" "$keyfile")"; then

    	chmod u-xs,g-xwrs,o-xwrt "$keyfile"

        elif test root:ssh_keys = "$(stat -c "%U:%G" "$keyfile")"; then
    	chmod u-xs,g-xws,o-xwrt "$keyfile"
        else
            echo "Key-like file '$keyfile' is owned by an unexpected user:group combination"
        fi
    done

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Find root:root-owned keys
      ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
        -type f -group root -perm /u+xs,g+xwrs,o+xwrt
      register: root_owned_keys
      changed_when: false
      failed_when: false
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040420
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_private_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Set permissions for root:root-owned keys
      ansible.builtin.file:
        path: '{{ item }}'
        mode: u-xs,g-xwrs,o-xwrt
        state: file
      with_items:
      - '{{ root_owned_keys.stdout_lines }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040420
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_private_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Find root:ssh_keys-owned keys
      ansible.builtin.command: find -H /etc/ssh/ -maxdepth 1 -user root -regex ".*_key$"
        -type f -group ssh_keys -perm /u+xs,g+xws,o+xwrt
      register: dedicated_group_owned_keys
      changed_when: false
      failed_when: false
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040420
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_private_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Set permissions for root:ssh_keys-owned keys
      ansible.builtin.file:
        path: '{{ item }}'
        mode: u-xs,g-xws,o-xwrt
        state: file
      with_items:
      - '{{ dedicated_group_owned_keys.stdout_lines }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040420
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_private_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

Remediation Puppet snippet ⇲

    include ssh_private_key_perms

    class ssh_private_key_perms {
      exec { 'sshd_priv_key':
        command => "chmod 0640 /etc/ssh/*_key",
        path    => '/bin:/usr/bin'
      }
    }

#### Rule Verify Permissions on SSH Server Public *.pub Key Files [ref]

To properly set the permissions of `/etc/ssh/*.pub`, run the command:

    $ sudo chmod 0644 /etc/ssh/*.pub

Rationale: | If a public host key file is modified by an unauthorized user, the SSH service may be compromised.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_file_permissions_sshd_pub_key

Identifiers and References

References: 12, 13, 14, 15, 16, 18, 3, 5, APO01.06, DSS05.04, DSS05.07, DSS06.02, 3.1.13, 3.13.10, CCI-000366, 4.3.3.7.3, SR 2.1, SR 5.2, A.10.1.1, A.11.1.4, A.11.1.5, A.11.2.1, A.13.1.1, A.13.1.3, A.13.2.1, A.13.2.3, A.13.2.4, A.14.1.2, A.14.1.3, A.6.1.2, A.7.1.1, A.7.1.2, A.7.3.1, A.8.2.2, A.8.2.3, A.9.1.1, A.9.1.2, A.9.2.3, A.9.4.1, A.9.4.4, A.9.4.5, CIP-003-8 R5.1.1, CIP-003-8 R5.3, CIP-004-6 R2.3, CIP-007-3 R2.1, CIP-007-3 R2.2, CIP-007-3 R2.3, CIP-007-3 R5.1, CIP-007-3 R5.1.1, CIP-007-3 R5.1.2, AC-17(a), CM-6(a), AC-6(1), PR.AC-4, PR.DS-5, Req-2.2.4, 2.2.6, SRG-OS-000480-GPOS-00227, OL07-00-040410, SV-221858r603260_rule

Remediation Shell script ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; then

    find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt  -type f -regex '^.*\.pub$' -exec chmod u-xs,g-xws,o-xwt {} \;

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | low
Reboot: | false
Strategy: | configure

    - name: Find /etc/ssh/ file(s)
      command: find -H /etc/ssh/ -maxdepth 1 -perm /u+xs,g+xws,o+xwt  -type f -regex "^.*\.pub$"
      register: files_found
      changed_when: false
      failed_when: false
      check_mode: false
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040410
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_pub_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

    - name: Set permissions for /etc/ssh/ file(s)
      file:
        path: '{{ item }}'
        mode: u-xs,g-xws,o-xwt
        state: file
      with_items:
      - '{{ files_found.stdout_lines }}'
      when: ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - DISA-STIG-OL07-00-040410
      - NIST-800-171-3.1.13
      - NIST-800-171-3.13.10
      - NIST-800-53-AC-17(a)
      - NIST-800-53-AC-6(1)
      - NIST-800-53-CM-6(a)
      - PCI-DSS-Req-2.2.4
      - PCI-DSSv4-2.2.6
      - configure_strategy
      - file_permissions_sshd_pub_key
      - low_complexity
      - low_disruption
      - medium_severity
      - no_reboot_needed

Remediation Puppet snippet ⇲

    include ssh_public_key_perms

    class ssh_public_key_perms {
      exec { 'sshd_pub_key':
        command => "chmod 0644 /etc/ssh/*.pub",
        path    => '/bin:/usr/bin'
      }
    }

Group System Security Services Daemon Group contains 2 rules

[ref] The System Security Services Daemon (SSSD) is a system daemon that provides access to different identity and authentication providers such as Red Hat's IdM, Microsoft's AD, openLDAP, MIT Kerberos, etc. It uses a common framework that can provide caching and offline support to systems utilizing SSSD. SSSD using caching to reduce load on authentication servers permit offline authentication as well as store extended user data.
For more information, see https://docs.oracle.com/en/operating-systems/oracle-linux/7/userauth/userauth-AuthenticationConfiguration.html#ol7-sssd-auth

#### Rule Enable Smartcards in SSSD [ref]

SSSD should be configured to authenticate access to the system using smart cards. To enable smart cards in SSSD, set `pam_cert_auth` to `True` under the `[pam]` section in `/etc/sssd/sssd.conf`. For example:

    [pam]
    pam_cert_auth = True

Rationale:

Using an authentication device, such as a CAC or token that is separate from the information system, ensures that even if the information system is compromised, that compromise will not affect credentials stored on the authentication device.
Multi-Factor Authentication (MFA) solutions that require devices separate from information systems gaining access include, for example, hardware tokens providing time-based or challenge-response authenticators and smart cards such as the U.S. Government Personal Identity Verification card and the DoD Common Access Card.

Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sssd_enable_smartcards
Identifiers and References | References: CCI-001954, CCI-000765, CCI-000766, CCI-000767, CCI-000768, 0421, 0422, 0431, 0974, 1173, 1401, 1504, 1505, 1546, 1557, 1558, 1559, 1560, 1561, Req-8.3, 8.4, SRG-OS-000375-GPOS-00160, SRG-OS-000105-GPOS-00052, SRG-OS-000106-GPOS-00053, SRG-OS-000107-GPOS-00054, SRG-OS-000108-GPOS-00055

Remediation Shell script ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q sssd-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    # sssd configuration files must be created with 600 permissions if they don't exist
    # otherwise the sssd module fails to start
    OLD_UMASK=$(umask)
    umask u=rw,go=

    found=false

    # set value in all files if they contain section or key
    for f in $(echo -n "/etc/sssd/sssd.conf"); do
        if [ ! -e "$f" ]; then
            continue
        fi

        # find key in section and change value
        if grep -qzosP "[[:space:]]*\[pam\]([^\n\[]*\n+)+?[[:space:]]*pam_cert_auth" "$f"; then
                sed -i "s/pam_cert_auth[^(\n)]*/pam_cert_auth = True/" "$f"
                found=true

        # find section and add key = value to it
        elif grep -qs "[[:space:]]*\[pam\]" "$f"; then
                sed -i "/[[:space:]]*\[pam\]/a pam_cert_auth = True" "$f"
                found=true
        fi
    done

    # if section not in any file, append section with key = value to FIRST file in files parameter
    if ! $found ; then
        file=$(echo "/etc/sssd/sssd.conf" | cut -f1 -d ' ')
        mkdir -p "$(dirname "$file")"
        echo -e "[pam]\npam_cert_auth = True" >> "$file"
    fi

    umask $OLD_UMASK

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | configure

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - PCI-DSS-Req-8.3
      - PCI-DSSv4-8.4
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_enable_smartcards

    - name: Test for domain group
      command: grep '^\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
      register: test_grep_domain
      ignore_errors: true
      changed_when: false
      check_mode: false
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - PCI-DSS-Req-8.3
      - PCI-DSSv4-8.4
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_enable_smartcards

    - name: Add default domain group (if no domain there)
      ini_file:
        path: /etc/sssd/sssd.conf
        section: '{{ item.section }}'
        option: '{{ item.option }}'
        value: '{{ item.value }}'
        create: true
        mode: 384
      with_items:
      - section: sssd
        option: domains
        value: default
      - section: domain/default
        option: id_provider
        value: files
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - test_grep_domain.stdout is defined
      - test_grep_domain.stdout | length < 1
      tags:
      - PCI-DSS-Req-8.3
      - PCI-DSSv4-8.4
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_enable_smartcards

    - name: Enable Smartcards in SSSD
      ini_file:
        dest: /etc/sssd/sssd.conf
        section: pam
        option: pam_cert_auth
        value: 'True'
        create: true
        mode: 384
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - PCI-DSS-Req-8.3
      - PCI-DSSv4-8.4
      - configure_strategy
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_enable_smartcards

#### Rule Configure SSSD to Expire SSH Known Hosts [ref]

SSSD should be configured to expire keys from known SSH hosts after `180` seconds. To configure SSSD to known SSH hosts, set `ssh_known_hosts_timeout` to `180` under the `[ssh]` section in `/etc/sssd/sssd.conf`. For example:

    [ssh]
    ssh_known_hosts_timeout = 180

Rationale: | If cached authentication information is out-of-date, the validity of the authentication information may be questionable.
Severity: | medium
Rule ID: | xccdf_org.ssgproject.content_rule_sssd_ssh_known_hosts_timeout

Identifiers and References

References: 1, 12, 15, 16, 5, DSS05.04, DSS05.05, DSS05.07, DSS05.10, DSS06.03, DSS06.10, CCI-002007, 4.3.3.2.2, 4.3.3.5.1, 4.3.3.5.2, 4.3.3.6.1, 4.3.3.6.2, 4.3.3.6.3, 4.3.3.6.4, 4.3.3.6.5, 4.3.3.6.6, 4.3.3.6.7, 4.3.3.6.8, 4.3.3.6.9, 4.3.3.7.2, 4.3.3.7.4, SR 1.1, SR 1.10, SR 1.2, SR 1.3, SR 1.4, SR 1.5, SR 1.7, SR 1.8, SR 1.9, SR 2.1, A.18.1.4, A.7.1.1, A.9.2.1, A.9.2.2, A.9.2.3, A.9.2.4, A.9.2.6, A.9.3.1, A.9.4.2, A.9.4.3, CM-6(a), IA-5(13), PR.AC-1, PR.AC-6, PR.AC-7, SRG-OS-000383-GPOS-00166

Remediation Shell script ⇲

    # Remediation is applicable only in certain platforms
    if rpm --quiet -q sssd-common && { [ ! -f /.dockerenv ] && [ ! -f /run/.containerenv ]; }; then

    var_sssd_ssh_known_hosts_timeout='180'

    # sssd configuration files must be created with 600 permissions if they don't exist
    # otherwise the sssd module fails to start
    OLD_UMASK=$(umask)
    umask u=rw,go=

    found=false

    # set value in all files if they contain section or key
    for f in $(echo -n "/etc/sssd/sssd.conf"); do
        if [ ! -e "$f" ]; then
            continue
        fi

        # find key in section and change value
        if grep -qzosP "[[:space:]]*\[ssh\]([^\n\[]*\n+)+?[[:space:]]*ssh_known_hosts_timeout" "$f"; then
                sed -i "s/ssh_known_hosts_timeout[^(\n)]*/ssh_known_hosts_timeout = $var_sssd_ssh_known_hosts_timeout/" "$f"
                found=true

        # find section and add key = value to it
        elif grep -qs "[[:space:]]*\[ssh\]" "$f"; then
                sed -i "/[[:space:]]*\[ssh\]/a ssh_known_hosts_timeout = $var_sssd_ssh_known_hosts_timeout" "$f"
                found=true
        fi
    done

    # if section not in any file, append section with key = value to FIRST file in files parameter
    if ! $found ; then
        file=$(echo "/etc/sssd/sssd.conf" | cut -f1 -d ' ')
        mkdir -p "$(dirname "$file")"
        echo -e "[ssh]\nssh_known_hosts_timeout = $var_sssd_ssh_known_hosts_timeout" >> "$file"
    fi

    umask $OLD_UMASK

    else
        >&2 echo 'Remediation is not applicable, nothing was done'
    fi

Remediation Ansible snippet ⇲

Complexity: | low
Disruption: | medium
Reboot: | false
Strategy: | unknown

    - name: Gather the package facts
      package_facts:
        manager: auto
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(13)
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_ssh_known_hosts_timeout
      - unknown_strategy
    - name: XCCDF Value var_sssd_ssh_known_hosts_timeout # promote to variable
      set_fact:
        var_sssd_ssh_known_hosts_timeout: !!str 180
      tags:
        - always

    - name: Test for domain group
      command: grep '\s*\[domain\/[^]]*]' /etc/sssd/sssd.conf
      register: test_grep_domain
      ignore_errors: true
      changed_when: false
      check_mode: false
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(13)
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_ssh_known_hosts_timeout
      - unknown_strategy

    - name: Add default domain group (if no domain there)
      ini_file:
        path: /etc/sssd/sssd.conf
        section: '{{ item.section }}'
        option: '{{ item.option }}'
        value: '{{ item.value }}'
        create: true
        mode: 384
      with_items:
      - section: sssd
        option: domains
        value: default
      - section: domain/default
        option: id_provider
        value: files
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      - test_grep_domain.stdout is defined
      - test_grep_domain.stdout | length < 1
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(13)
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_ssh_known_hosts_timeout
      - unknown_strategy

    - name: Configure SSSD to Expire SSH Known Hosts
      ini_file:
        dest: /etc/sssd/sssd.conf
        section: ssh
        option: ssh_known_hosts_timeout
        value: '{{ var_sssd_ssh_known_hosts_timeout }}'
        create: true
        mode: 384
      when:
      - '"sssd-common" in ansible_facts.packages'
      - ansible_virtualization_type not in ["docker", "lxc", "openvz", "podman", "container"]
      tags:
      - NIST-800-53-CM-6(a)
      - NIST-800-53-IA-5(13)
      - low_complexity
      - medium_disruption
      - medium_severity
      - no_reboot_needed
      - sssd_ssh_known_hosts_timeout
      - unknown_strategy

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