Rules with nist Reference in Guide to the Secure Configuration of Red Hat Enterprise Linux 6

Reference (nist) | Rule Title | Description | Rationale | Variable Setting

CM-7

Restrict Access to Anonymous Users if Possible

Is there a mission-critical reason for users to transfer files to/from their own accounts using FTP, rather than using a secure protocol like SCP/SFTP? If not, edit the vsftpd configuration file. Add or correct the following configuration option:

    local_enable=NO

If non-anonymous FTP logins are necessary, follow the guidance in the remainder of this section to secure these logins as much as possible.

The use of non-anonymous FTP logins is strongly discouraged. Since SSH clients and servers are widely available, and since SSH provides support for a transfer mode which resembles FTP in user interface, there is no good reason to allow password-based FTP access.

AC-3

Restrict Access to Anonymous Users if Possible

Is there a mission-critical reason for users to transfer files to/from their own accounts using FTP, rather than using a secure protocol like SCP/SFTP? If not, edit the vsftpd configuration file. Add or correct the following configuration option:

    local_enable=NO

If non-anonymous FTP logins are necessary, follow the guidance in the remainder of this section to secure these logins as much as possible.

The use of non-anonymous FTP logins is strongly discouraged. Since SSH clients and servers are widely available, and since SSH provides support for a transfer mode which resembles FTP in user interface, there is no good reason to allow password-based FTP access.

CM-7

Install vsftpd Package

If this system must operate as an FTP server, install the `vsftpd` package via the standard channels.

    $ sudo yum install vsftpd

After Red Hat Enterprise Linux 2.1, Red Hat switched from distributing wu-ftpd with Red Hat Enterprise Linux to distributing vsftpd. For security and for consistency with future Red Hat releases, the use of vsftpd is recommended.

CM-7

Disable vsftpd Service

The `vsftpd` service can be disabled with the following command:

    $ sudo chkconfig vsftpd off

Running FTP server software provides a network-based avenue of attack, and should be disabled if not needed. Furthermore, the FTP protocol is unencrypted and creates a risk of compromising sensitive information.

CM-7

Uninstall vsftpd Package

The `vsftpd` package can be removed with the following command:

    $ sudo yum erase vsftpd

Removing the vsftpd package decreases the risk of its accidental activation.

CM-7

Disable httpd Service

The `httpd` service can be disabled with the following command:

    $ sudo chkconfig httpd off

Running web server software provides a network-based avenue of attack, and should be disabled if not needed.

CM-7

Uninstall httpd Package

The `httpd` package can be removed with the following command:

    $ sudo yum erase httpd

If there is no need to make the web server software available, removing it provides a safeguard against its activation.

CM-7

Set httpd ServerTokens Directive to Prod

`ServerTokens Prod` restricts information in page headers, returning only the word "Apache."
Add or correct the following directive in `/etc/httpd/conf/httpd.conf`:

    ServerTokens Prod

Information disclosed to clients about the configuration of the web server and system could be used to plan an attack on the given system. This information disclosure should be restricted to a minimum.

CM-7

Set httpd ServerSignature Directive to Off

`ServerSignature Off` restricts `httpd` from displaying server version number on error pages.
Add or correct the following directive in `/etc/httpd/conf/httpd.conf`:

    ServerSignature Off

Information disclosed to clients about the configuration of the web server and system could be used to plan an attack on the given system. This information disclosure should be restricted to a minimum.

CM-7

Set Permissions on All Configuration Files Inside /etc/httpd/conf/

Set permissions on the web server configuration files to 640:

    $ sudo chmod 640 /etc/httpd/conf/*

Access to the web server's configuration files may allow an unauthorized user or attacker to access information about the web server or to alter the server's configuration files.

CM-7

Set Permissions on the /var/log/httpd/ Directory

Ensure that the permissions on the web server log directory is set to 700:

    $ sudo chmod 700 /var/log/httpd/

This is its default setting.

Access to the web server's log files may allow an unauthorized user or attacker to access information about the web server or alter the server's log files.

IA-5(10)

Configure SSSD's Memory Cache to Expire

SSSD's memory cache should be configured to set to expire records after 1 day. To configure SSSD to expire memory cache, set `memcache_timeout` to `86400` under the `[nss]` section in `/etc/sssd/sssd.conf`. For example:

    [nss]
    memcache_timeout = 86400

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

IA-5(13)

Configure SSSD's Memory Cache to Expire

SSSD's memory cache should be configured to set to expire records after 1 day. To configure SSSD to expire memory cache, set `memcache_timeout` to `86400` under the `[nss]` section in `/etc/sssd/sssd.conf`. For example:

    [nss]
    memcache_timeout = 86400

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

IA-5(13)

Configure SSSD to Expire Offline Credentials

SSSD should be configured to expire offline credentials after 1 day. To configure SSSD to expire offline credentials, set `offline_credentials_expiration` to `1` under the `[pam]` section in `/etc/sssd/sssd.conf`. For example:

    [pam]
    offline_credentials_expiration = 1

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

IA-5(13)

Configure SSSD to Expire Offline Credentials

SSSD should be configured to expire offline credentials after 1 day. To configure SSSD to expire offline credentials, set `offline_credentials_expiration` to `1` under the `[pam]` section in `/etc/sssd/sssd.conf`. For example:

    [pam]
    offline_credentials_expiration = 1

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

IA-5(10)

Install the SSSD Package

The `sssd` package should be installed. The `sssd` package can be installed with the following command:

    $ sudo yum install sssd

IA-5(10)

Install the SSSD Package

The `sssd` package should be installed. The `sssd` package can be installed with the following command:

    $ sudo yum install sssd

IA-5(13)

Configure SSSD to Expire SSH Known Hosts

SSSD should be configured to expire keys from known SSH hosts after 1 day. To configure SSSD to known SSH hosts, set `ssh_known_hosts_timeout` to `86400` under the `[ssh]` section in `/etc/sssd/sssd.conf`. For example:

    [ssh]
    ssh_known_hosts_timeout = 86400

If cached authentication information is out-of-date, the validity of the authentication information may be questionable.

IA-5(10)

Enable the SSSD Service

The SSSD service should be enabled. The `sssd` service can be enabled with the following command:

    $ sudo systemctl enable sssd.service

IA-5(10)

Enable the SSSD Service

The SSSD service should be enabled. The `sssd` service can be enabled with the following command:

    $ sudo systemctl enable sssd.service

CM-7

Disable DHCP Client

For each interface on the system (e.g. eth0), edit `/etc/sysconfig/network-scripts/ifcfg-interface` and make the following changes:

- Correct the BOOTPROTO line to read:

      BOOTPROTO=none

- Add or correct the following lines, substituting the appropriate values based on your site's addressing scheme:

      NETMASK=255.255.255.0
      IPADDR=192.168.1.2
      GATEWAY=192.168.1.1

DHCP relies on trusting the local network. If the local network is not trusted, then it should not be used. However, the automatic configuration provided by DHCP is commonly used and the alternative, manual configuration, presents an unacceptable burden in many circumstances.

CM-7

Deny BOOTP Queries

Unless your network needs to support older BOOTP clients, disable support for the bootp protocol by adding or correcting the global option:

    deny bootp;

The bootp option tells dhcpd to respond to BOOTP queries. If support for this simpler protocol is not needed, it should be disabled to remove attack vectors against the DHCP server.

CM-7

Do Not Use Dynamic DNS

To prevent the DHCP server from receiving DNS information from clients, edit `/etc/dhcp/dhcpd.conf`, and add or correct the following global option:

    ddns-update-style none;

The Dynamic DNS protocol is used to remotely update the data served by a DNS server. DHCP servers can use Dynamic DNS to publish information about their clients. This setup carries security risks, and its use is not recommended. If Dynamic DNS must be used despite the risks it poses, it is critical that Dynamic DNS transactions be protected using TSIG or some other cryptographic authentication mechanism. See dhcpd.conf(5) for more information about protecting the DHCP server from passing along malicious DNS data from its clients.

CM-7

Minimize Served Information

Edit /etc/dhcp/dhcpd.conf. Examine each address range section within the file, and ensure that the following options are not defined unless there is an operational need to provide this information via DHCP:

    option domain-name
    option domain-name-servers
    option nis-domain
    option nis-servers
    option ntp-servers
    option routers
    option time-offset

Because the configuration information provided by the DHCP server could be maliciously provided to clients by a rogue DHCP server, the amount of information provided via DHCP should be minimized. Remove these definitions from the DHCP server configuration to ensure that legitimate clients do not unnecessarily rely on DHCP for this information.

CM-7

Deny Decline Messages

Edit `/etc/dhcp/dhcpd.conf` and add or correct the following global option to prevent the DHCP server from responding the DHCPDECLINE messages, if possible:

    deny declines;

The DHCPDECLINE message can be sent by a DHCP client to indicate that it does not consider the lease offered by the server to be valid. By issuing many DHCPDECLINE messages, a malicious client can exhaust the DHCP server's pool of IP addresses, causing the DHCP server to forget old address allocations.

AU-12

Configure Logging

Ensure that the following line exists in `/etc/rsyslog.conf`:

    daemon.*           /var/log/daemon.log

Configure logwatch or other log monitoring tools to summarize error conditions reported by the dhcpd process.

By default, dhcpd logs notices to the daemon facility. Sending all daemon messages to a dedicated log file is part of the syslog configuration outlined in the Logging and Auditing section

CM-7

Uninstall DHCP Server Package

If the system does not need to act as a DHCP server, the dhcp package can be uninstalled. The `dhcp` package can be removed with the following command:

    $ sudo yum erase dhcp

Removing the DHCP server ensures that it cannot be easily or accidentally reactivated and disrupt network operation.

CM-7

Disable DHCP Service

The `dhcpd` service should be disabled on any system that does not need to act as a DHCP server. The `dhcpd` service can be disabled with the following command:

    $ sudo chkconfig dhcpd off

Unmanaged or unintentionally activated DHCP servers may provide faulty information to clients, interfering with the operation of a legitimate site DHCP server if there is one.

AU-8(1)

Enable the NTP Daemon

The `ntpd` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 ntpd on

Enabling the `ntpd` service ensures that the `ntpd` service 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 NTP daemon offers all of the functionality of `ntpdate`, which is now deprecated. Additional information on this is available at http://support.ntp.org/bin/view/Dev/DeprecatingNtpdate

AU-8(1)

Specify Additional Remote NTP Servers

Additional NTP servers can be specified for time synchronization in the file `/etc/ntp.conf`. To do so, add additional lines of the following form, substituting the IP address or hostname of a remote NTP server for ntpserver:

    server ntpserver

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.

AU-8(1)

Specify a Remote NTP Server

To specify a remote NTP server for time synchronization, edit the file `/etc/ntp.conf`. 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.

Synchronizing with an NTP server makes it possible to collate system logs from multiple sources or correlate computer events with real time events.

CM-7

Disable Printer Browsing Entirely if Possible

By default, CUPS listens on the network for printer list broadcasts on UDP port 631. This functionality is called printer browsing. To disable printer browsing entirely, edit the CUPS configuration file, located at `/etc/cups/cupsd.conf`, to include the following:

    Browsing Off

The CUPS print service can be configured to broadcast a list of available printers to the network. Other systems on the network, also running the CUPS print service, can be configured to listen to these broadcasts and add and configure these printers for immediate use. By disabling this browsing capability, the system will no longer generate or receive such broadcasts.

CM-7

Disable Print Server Capabilities

To prevent remote users from potentially connecting to and using locally configured printers, disable the CUPS print server sharing capabilities. To do so, limit how the server will listen for print jobs by removing the more generic port directive from /etc/cups/cupsd.conf:

    Port 631

and replacing it with the `Listen` directive:

    Listen localhost:631

This will prevent remote users from printing to locally configured printers while still allowing local users on the system to print normally.

By default, locally configured printers will not be shared over the network, but if this functionality has somehow been enabled, these recommendations will disable it again. Be sure to disable outgoing printer list broadcasts, or remote users will still be able to see the locally configured printers, even if they cannot actually print to them. To limit print serving to a particular set of users, use the Policy directive.

CM-7

Disable the CUPS Service

The `cups` service can be disabled with the following command:

    $ sudo chkconfig cups off

Turn off unneeded services to reduce attack surface.

CM-7

Disable rlogin Service

The `rlogin` service, which is available with the `rsh-server` package and runs as a service through xinetd, should be disabled. The `rlogin` service can be disabled with the following command:

    $ sudo chkconfig rlogin off

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.

IA-5(1)(c)

Disable rlogin Service

The `rlogin` service, which is available with the `rsh-server` package and runs as a service through xinetd, should be disabled. The `rlogin` service can be disabled with the following command:

    $ sudo chkconfig rlogin off

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.

CM-7

Disable rexec Service

The `rexec` service, which is available with the `rsh-server` package and runs as a service through xinetd, should be disabled. The `rexec` service can be disabled with the following command:

    $ sudo chkconfig rexec off

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.

CM-7

Disable rsh Service

The `rsh` service, which is available with the `rsh-server` package and runs as a service through xinetd, should be disabled. The `rsh` service can be disabled with the following command:

    $ sudo chkconfig rsh off

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.

IA-5(1)(c)

Disable rsh Service

The `rsh` service, which is available with the `rsh-server` package and runs as a service through xinetd, should be disabled. The `rsh` service can be disabled with the following command:

    $ sudo chkconfig rsh off

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.

CM-7

Uninstall rsh-server Package

The `rsh-server` package can be uninstalled with the following command:

    $ sudo yum erase rsh-server

The `rsh-server` package provides several obsolete and insecure network services. Removing it decreases the risk of those services' accidental (or intentional) activation.

CM-7

Remove Rsh Trust Files

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

Trust files are convenient, but when used in conjunction with the R-services, they can allow unauthenticated access to a system.

CM-7

Uninstall telnet-server Package

The `telnet-server` package can be uninstalled with the following command:

    $ sudo yum erase telnet-server

Removing the `telnet-server` package decreases the risk of the telnet service's accidental (or intentional) activation.

CM-7

Disable telnet Service

The `telnet` service can be disabled with the following command:

    $ sudo chkconfig telnet off

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.

IA-5(1)(c)

Disable telnet Service

The `telnet` service can be disabled with the following command:

    $ sudo chkconfig telnet off

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.

CM-7

Disable ypbind Service

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 chkconfig ypbind off

Disabling the `ypbind` service ensures the system is not acting as a client in a NIS or NIS+ domain.

CM-7

Uninstall ypserv Package

The `ypserv` package can be uninstalled with the following command:

    $ sudo yum erase ypserv

Removing the `ypserv` package decreases the risk of the accidental (or intentional) activation of NIS or NIS+ services.

CM-7

Disable tftp Service

The `tftp` service should be disabled. The `tftp` service can be disabled with the following command:

    $ sudo chkconfig tftp off

Disabling the `tftp` service ensures the system is not acting as a TFTP server, which does not provide encryption or authentication.

CM-7

Ensure tftp Daemon Uses Secure Mode

If running the `tftp` service is necessary, it should be configured to change its root directory at startup. To do so, ensure `/etc/xinetd.d/tftp` includes `-s` as a command line argument, as shown in the following example (which is also the default):

    server_args = -s /var/lib/tftpboot

Using the `-s` option causes the TFTP service to only serve files from the given directory. Serving files from an intentionally-specified directory reduces the risk of sharing files which should remain private.

CM-7

Uninstall tftp-server Package

The `tftp-server` package can be removed with the following command:

    $ sudo yum erase tftp-server

Removing the `tftp-server` package decreases the risk of the accidental (or intentional) activation of tftp services.

CM-7

Disable xinetd Service

The `xinetd` service can be disabled with the following command:

    $ sudo chkconfig xinetd off

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.

CM-7

Uninstall xinetd Package

The `xinetd` package can be uninstalled with the following command:

    $ sudo yum erase xinetd

Removing the `xinetd` package decreases the risk of the xinetd service's accidental (or intentional) activation.

CM-7

Disable anacron Service

The `cronie-anacron` package, which provides `anacron` functionality, is installed by default. The `cronie-anacron` package can be removed with the following command:

    $ sudo yum erase cronie-anacron

The `anacron` service provides `cron` functionality for systems such as laptops and workstations that may be shut down during the normal times that `cron` jobs are scheduled to run. On systems which do not require this additional functionality, `anacron` could needlessly increase the possible attack surface for an intruder.

CM-7

Enable cron Service

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 chkconfig --level 2345 crond on

Due to its usage for maintenance and security-supporting tasks, enabling the cron daemon is essential.

CM-7

Disable At Service (atd)

The `at` and `batch` commands can be used to schedule tasks that are meant to be executed only once. This allows delayed execution in a manner similar to cron, except that it is not recurring. The daemon `atd` keeps track of tasks scheduled via `at` and `batch`, and executes them at the specified time. The `atd` service can be disabled with the following command:

    $ sudo chkconfig atd off

The `atd` service could be used by an unsophisticated insider to carry out activities outside of a normal login session, which could complicate accountability. Furthermore, the need to schedule tasks with `at` or `batch` is not common.

CM-7 | Mount Remote Filesystems with nodev | Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of any NFS mounts. | Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users. |
MP-2 | Mount Remote Filesystems with nodev | Add the `nodev` option to the fourth column of `/etc/fstab` for the line which controls mounting of any NFS mounts. | Legitimate device files should only exist in the /dev directory. NFS mounts should not present device files to users. |

CM-7

Disable Control Group Rules Engine (cgred)

The `cgred` service moves tasks into control groups according to parameters set in the `/etc/cgrules.conf` configuration file. The `cgred` service can be disabled with the following command:

    $ sudo chkconfig cgred off

Unless control groups are used to manage system resources, running the cgred service service is not necessary.

CM-7

Disable D-Bus IPC Service (messagebus)

D-Bus provides an IPC mechanism used by a growing list of programs, such as those used for Gnome, Bluetooth, and Avahi. Due to these dependencies, disabling D-Bus may not be practical for many systems. The `messagebus` service can be disabled with the following command:

    $ sudo chkconfig messagebus off

If no services which require D-Bus are needed, then it can be disabled. As a broker for IPC between processes of different privilege levels, it could be a target for attack. However, disabling D-Bus is likely to be impractical for any system which needs to provide a graphical login session.

CM-7

Disable Advanced Configuration and Power Interface (acpid)

The Advanced Configuration and Power Interface Daemon (`acpid`) dispatches ACPI events (such as power/reset button depressed) to userspace programs. The `acpid` service can be disabled with the following command:

    $ sudo chkconfig acpid off

ACPI support is highly desirable for systems in some network roles, such as laptops or desktops. For other systems, such as servers, it may permit accidental or trivially achievable denial of service situations and disabling it is appropriate.

AC-4

Disable Network Router Discovery Daemon (rdisc)

The `rdisc` service implements the client side of the ICMP Internet Router Discovery Protocol (IRDP), which allows discovery of routers on the local subnet. If a router is discovered then the local routing table is updated with a corresponding default route. By default this daemon is disabled. The `rdisc` service can be disabled with the following command:

    $ sudo chkconfig rdisc off

General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.

CM-7

Disable Network Router Discovery Daemon (rdisc)

The `rdisc` service implements the client side of the ICMP Internet Router Discovery Protocol (IRDP), which allows discovery of routers on the local subnet. If a router is discovered then the local routing table is updated with a corresponding default route. By default this daemon is disabled. The `rdisc` service can be disabled with the following command:

    $ sudo chkconfig rdisc off

General-purpose systems typically have their network and routing information configured statically by a system administrator. Workstations or some special-purpose systems often use DHCP (instead of IRDP) to retrieve dynamic network configuration information.

CM-7

Disable CPU Speed (cpuspeed)

The `cpuspeed` service can adjust the clock speed of supported CPUs based upon the current processing load thereby conserving power and reducing heat. The `cpuspeed` service can be disabled with the following command:

    $ sudo chkconfig cpuspeed off

The `cpuspeed` service is only necessary if adjusting the CPU clock speed provides benefit. Traditionally this has included laptops (to enhance battery life), but may also apply to server or desktop environments where conserving power is highly desirable or necessary.

CM-7

Disable Network Console (netconsole)

The `netconsole` service is responsible for loading the netconsole kernel module, which logs kernel printk messages over UDP to a syslog server. This allows debugging of problems where disk logging fails and serial consoles are impractical. The `netconsole` service can be disabled with the following command:

    $ sudo chkconfig netconsole off

The `netconsole` service is not necessary unless there is a need to debug kernel panics, which is not common.

CM-7

Disable Certmonger Service (certmonger)

Certmonger is a D-Bus based service that attempts to simplify interaction with certifying authorities on networks which use public-key infrastructure. It is often combined with Red Hat's IPA (Identity Policy Audit) security information management solution to aid in the management of certificates. The `certmonger` service can be disabled with the following command:

    $ sudo chkconfig certmonger off

The services provided by certmonger may be essential for systems fulfilling some roles a PKI infrastructure, but its functionality is not necessary for many other use cases.

CM-7

Disable Quota Netlink (quota_nld)

The `quota_nld` service provides notifications to users of disk space quota violations. It listens to the kernel via a netlink socket for disk quota violations and notifies the appropriate user of the violation using D-Bus or by sending a message to the terminal that the user has last accessed. The `quota_nld` service can be disabled with the following command:

    $ sudo chkconfig quota_nld off

If disk quotas are enforced on the local system, then the `quota_nld` service likely provides useful functionality and should remain enabled. However, if disk quotas are not used or user notification of disk quota violation is not desired then there is no need to run this service.

AU-12

Enable Process Accounting (psacct)

The process accounting service, `psacct`, works with programs including `acct` and `ac` to allow system administrators to view user activity, such as commands issued by users of the system. The `psacct` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 psacct on

The `psacct` service can provide administrators a convenient view into some user activities. However, it should be noted that the auditing system and its audit records provide more authoritative and comprehensive records.

CM-7

Enable Process Accounting (psacct)

The process accounting service, `psacct`, works with programs including `acct` and `ac` to allow system administrators to view user activity, such as commands issued by users of the system. The `psacct` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 psacct on

The `psacct` service can provide administrators a convenient view into some user activities. However, it should be noted that the auditing system and its audit records provide more authoritative and comprehensive records.

CM-7

Disable Red Hat Network Service (rhnsd)

The Red Hat Network service automatically queries Red Hat Network servers to determine whether there are any actions that should be executed, such as package updates. This only occurs if the system was registered to an RHN server or satellite and managed as such. The `rhnsd` service can be disabled with the following command:

    $ sudo chkconfig rhnsd off

Although systems management and patching is extremely important to system security, management by a system outside the enterprise enclave is not desirable for some environments. However, if the system is being managed by RHN or RHN Satellite Server the `rhnsd` daemon can remain on.

CM-7

Disable Software RAID Monitor (mdmonitor)

The `mdmonitor` service is used for monitoring a software RAID array; hardware RAID setups do not use this service. The `mdmonitor` service can be disabled with the following command:

    $ sudo chkconfig mdmonitor off

If software RAID monitoring is not required, there is no need to run this service.

CM-7

Enable IRQ Balance (irqbalance)

The `irqbalance` service optimizes the balance between power savings and performance through distribution of hardware interrupts across multiple processors. The `irqbalance` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 irqbalance on

In an environment with multiple processors (now common), the irqbalance service provides potential speedups for handling interrupt requests.

CM-7

Disable Odd Job Daemon (oddjobd)

The `oddjobd` service exists to provide an interface and access control mechanism through which specified privileged tasks can run tasks for unprivileged client applications. Communication with `oddjobd` through the system message bus. The `oddjobd` service can be disabled with the following command:

    $ sudo chkconfig oddjobd off

The `oddjobd` service may provide necessary functionality in some environments, and can be disabled if it is not needed. Execution of tasks by privileged programs, on behalf of unprivileged ones, has traditionally been a source of privilege escalation security issues.

CM-7

Disable Hardware Abstraction Layer Service (haldaemon)

The Hardware Abstraction Layer Daemon (`haldaemon`) collects and maintains information about the system's hardware configuration. This service is required on a workstation running a desktop environment, and may be necessary on any system which deals with removable media or devices. The `haldaemon` service can be disabled with the following command:

    $ sudo chkconfig haldaemon off

The haldaemon provides essential functionality on systems that use removable media or devices, but can be disabled for systems that do not require these.

CM-7

Disable SMART Disk Monitoring Service (smartd)

SMART (Self-Monitoring, Analysis, and Reporting Technology) is a feature of hard drives that allows them to detect symptoms of disk failure and relay an appropriate warning. The `smartd` service can be disabled with the following command:

    $ sudo chkconfig smartd off

SMART can help protect against denial of service due to failing hardware. Nevertheless, if it is not needed or the system's drives are not SMART-capable (such as solid state drives), it can be disabled.

CM-7

Disable Apache Qpid (qpidd)

The `qpidd` service provides high speed, secure, guaranteed delivery services. It is an implementation of the Advanced Message Queuing Protocol. By default the qpidd service will bind to port 5672 and listen for connection attempts. The `qpidd` service can be disabled with the following command:

    $ sudo chkconfig qpidd off

The qpidd service is automatically installed when the "base" package selection is selected during installation. The qpidd service listens for network connections, which increases the attack surface of the system. If the system is not intended to receive AMQP traffic, then the `qpidd` service is not needed and should be disabled or removed.

CM-7

Disable Automatic Bug Reporting Tool (abrtd)

The Automatic Bug Reporting Tool (`abrtd`) daemon collects and reports crash data when an application crash is detected. Using a variety of plugins, abrtd 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 `abrtd` service can be disabled with the following command:

    $ sudo chkconfig abrtd off

Mishandling crash data could expose sensitive information about vulnerabilities in software executing on the local system, as well as sensitive information from within a process's address space or registers.

CM-7

Disable Control Group Config (cgconfig)

Control groups allow an administrator to allocate system resources (such as CPU, memory, network bandwidth, etc) among a defined group (or groups) of processes executing on a system. The `cgconfig` daemon starts at boot and establishes the predefined control groups. The `cgconfig` service can be disabled with the following command:

    $ sudo chkconfig cgconfig off

Unless control groups are used to manage system resources, running the cgconfig service is not necessary.

CM-7

Disable Cyrus SASL Authentication Daemon (saslauthd)

The `saslauthd` service handles plaintext authentication requests on behalf of the SASL library. The service isolates all code requiring superuser privileges for SASL authentication into a single process, and can also be used to provide proxy authentication services to clients that do not understand SASL based authentication. The `saslauthd` service can be disabled with the following command:

    $ sudo chkconfig saslauthd off

The `saslauthd` service provides essential functionality for performing authentication in some directory environments, such as those which use Kerberos and LDAP. For others, however, in which only local files may be consulted, it is not necessary and should be disabled.

CM-7

Disable ntpdate Service (ntpdate)

The `ntpdate` service sets the local hardware clock by polling NTP servers when the system boots. It synchronizes to the NTP servers listed in `/etc/ntp/step-tickers` or `/etc/ntp.conf` and then sets the local hardware clock to the newly synchronized system time. The `ntpdate` service can be disabled with the following command:

    $ sudo chkconfig ntpdate off

The `ntpdate` service may only be suitable for systems which are rebooted frequently enough that clock drift does not cause problems between reboots. In any event, the functionality of the ntpdate service is now available in the ntpd program and should be considered deprecated.

CM-7

Disable KDump Kernel Crash Analyzer (kdump)

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 chkconfig kdump off

Unless the system is used for kernel development or testing, there is little need to run the kdump service.

CM-7

Disable Red Hat Subscription Manager Daemon (rhsmcertd)

The Red Hat Subscription Manager (rhsmcertd) periodically checks for changes in the entitlement certificates for a registered system and updates it accordingly. The `rhsmcertd` service can be disabled with the following command:

    $ sudo chkconfig rhsmcertd off

The `rhsmcertd` service can provide administrators with some additional control over which of their systems are entitled to particular subscriptions. However, for systems that are managed locally or which are not expected to require remote changes to their subscription status, it is unnecessary and can be disabled.

CM-7

Disable Portreserve (portreserve)

The `portreserve` service is a TCP port reservation utility that can be used to prevent portmap from binding to well known TCP ports that are required for other services. The `portreserve` service can be disabled with the following command:

    $ sudo chkconfig portreserve off

The `portreserve` service provides helpful functionality by preventing conflicting usage of ports in the reserved port range, but it can be disabled if not needed.

CM-7

Disable System Statistics Reset Service (sysstat)

The `sysstat` service resets various I/O and CPU performance statistics to zero in order to begin counting from a fresh state at boot time. The `sysstat` service can be disabled with the following command:

    $ sudo chkconfig sysstat off

By default the `sysstat` service merely runs a program at boot to reset the statistics, which can be retrieved using programs such as `sar` and `sadc`. These may provide useful insight into system operation, but unless used this service can be disabled.

AC-3

Disable SSH Support for .rhosts Files

SSH can emulate the behavior of the obsolete rsh command in allowing users to enable insecure access to their accounts via `.rhosts` files.
To ensure this behavior is disabled, add or correct the following line in `/etc/ssh/sshd_config`:

    IgnoreRhosts yes

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

AC-3

Limit Users' SSH Access

By default, the SSH configuration allows any user with an account to access the system. In order to specify the users that are allowed to login via SSH and deny all other users, add or correct the following line in the `/etc/ssh/sshd_config` file:

    DenyUsers USER1 USER2

Where `USER1` and `USER2` are valid user names.

Specifying which accounts are allowed SSH access into the system reduces the possibility of unauthorized access to the system.

AC-2(5)

Set SSH Idle Timeout Interval

SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out.
To set an idle timeout interval, edit the following line in `/etc/ssh/sshd_config` as follows:

    ClientAliveInterval

The timeout interval is given in seconds. To have a timeout of 15 minutes, set interval to 900.
If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made here. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.

Causing idle users to be automatically logged out guards against compromises one system leading trivially to compromises on another.

SA-8

Set SSH Idle Timeout Interval

SSH allows administrators to set an idle timeout interval. After this interval has passed, the idle user will be automatically logged out.
To set an idle timeout interval, edit the following line in `/etc/ssh/sshd_config` as follows:

    ClientAliveInterval

The timeout interval is given in seconds. To have a timeout of 15 minutes, set interval to 900.
If a shorter timeout has already been set for the login shell, that value will preempt any SSH setting made here. Keep in mind that some processes may stop SSH from correctly detecting that the user is idle.

Causing idle users to be automatically logged out guards against compromises one system leading trivially to compromises on another.

AC-9

Print Last Log

When enabled, SSH will display the date and time of the last successful account logon. To enable LastLog in SSH, add or correct the following line in the `/etc/ssh/sshd_config` file:

    PrintLastLog yes

Providing users feedback on when account accesses last occurred facilitates user recognition and reporting of unauthorized account use.

AC-8(a)

Enable SSH Warning Banner

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.

The warning message reinforces policy awareness during the login 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.

AC-3

Disable SSH Access via Empty Passwords

To explicitly disallow remote 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.

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.

AC-17(2)

Use Only Approved MACs

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

IA-7

Use Only Approved MACs

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

SC-13

Use Only Approved MACs

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

AC-3

Use Only Approved Ciphers

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

AC-17(2)

Use Only Approved Ciphers

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

SI-7

Use Only Approved Ciphers

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

IA-5(1)(c)

Use Only Approved Ciphers

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

IA-7

Use Only Approved Ciphers

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.

Approved algorithms should impart some level of confidence in their implementation. These are also required for compliance.

AC-2(5)

Set SSH Client Alive Count

To ensure the SSH idle timeout occurs precisely when the `ClientAliveCountMax` is set, edit `/etc/ssh/sshd_config` as follows:

    ClientAliveCountMax 0

This ensures a user login will be terminated as soon as the `ClientAliveCountMax` is reached.

SA-8

Set SSH Client Alive Count

To ensure the SSH idle timeout occurs precisely when the `ClientAliveCountMax` is set, edit `/etc/ssh/sshd_config` as follows:

    ClientAliveCountMax 0

This ensures a user login will be terminated as soon as the `ClientAliveCountMax` is reached.

AC-3

Disable Host-Based Authentication

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.
To disable host-based authentication, add or correct the following line in `/etc/ssh/sshd_config`:

    HostbasedAuthentication no

SSH trust relationships mean a compromise on one host can allow an attacker to move trivially to other hosts.

AC-3(10)

Allow Only SSH Protocol 2

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

SSH protocol version 1 suffers from design flaws that result in security vulnerabilities and should not be used.

IA-5(1)(c)

Allow Only SSH Protocol 2

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

SSH protocol version 1 suffers from design flaws that result in security vulnerabilities and should not be used.

AC-3

Disable SSH Root Login

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

Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.

AC-6(2)

Disable SSH Root Login

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

Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.

IA-2(1)

Disable SSH Root Login

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

Permitting direct root login reduces auditable information about who ran privileged commands on the system and also allows direct attack attempts on root's password.

CM-7

Authenticate Zone Transfers

If it is necessary for a secondary nameserver to receive zone data via zone transfer from the primary server, follow the instructions here. Use dnssec-keygen to create a symmetric key file in the current directory:

    $ cd /tmp
    $ sudo dnssec-keygen -a HMAC-MD5 -b 128 -n HOST dns.example.com
    Kdns.example.com .+aaa +iiiii

This output is the name of a file containing the new key. Read the file to find the base64-encoded key string:

    $ sudo cat Kdns.example.com .+NNN +MMMMM .key
    dns.example.com IN KEY 512 3 157 base64-key-string

Add the directives to `/etc/named.conf` on the primary server:

    key zone-transfer-key {
      algorithm hmac-md5;
      secret "base64-key-string ";
    };
    zone "example.com " IN {
      type master;
      allow-transfer { key zone-transfer-key; };
      ...
    };

Add the directives below to `/etc/named.conf` on the secondary nameserver:

    key zone-transfer-key {
      algorithm hmac-md5;
      secret "base64-key-string ";
    };

    server IP-OF-MASTER {
      keys { zone-transfer-key; };
    };

    zone "example.com " IN {
      type slave;
      masters { IP-OF-MASTER ; };
      ...
    };

The BIND transaction signature (TSIG) functionality allows primary and secondary nameservers to use a shared secret to verify authorization to perform zone transfers. This method is more secure than using IP-based limiting to restrict nameserver access, since IP addresses can be easily spoofed. However, if you cannot configure TSIG between your servers because, for instance, the secondary nameserver is not under your control and its administrators are unwilling to configure TSIG, you can configure an allow-transfer directive with numerical IP addresses or ACLs as a last resort.

CM-7

Disable DNS Server

The `named` service can be disabled with the following command:

    $ sudo chkconfig named off

All network services involve some risk of compromise due to implementation flaws and should be disabled if possible.

CM-7

Uninstall bind Package

To remove the `bind` package, which contains the `named` service, run the following command:

    $ sudo yum erase bind

If there is no need to make DNS server software available, removing it provides a safeguard against its activation.

CM-7

Uninstall openldap-servers Package

The `openldap-servers` package should be removed if not in use. Is this system the OpenLDAP server? If not, remove the package.

    $ sudo yum erase openldap-servers

The openldap-servers RPM is not installed by default on Red Hat Enterprise Linux 6 systems. It is needed only by the OpenLDAP server, not by the clients which use LDAP for authentication. If the system is not intended for use as an LDAP Server it should be removed.

The `openldap-servers` package is not installed by default on RHEL6 systems. It is needed only by the OpenLDAP server system, not clients which use LDAP for authentication. If the system is not intended for use as an LDAP server, `openldap-servers` should be removed.

CM-7

Configure LDAP Client to Use TLS For All Transactions

Configure LDAP to enforce TLS use. First, edit the file `/etc/pam_ldap.conf`, and add or correct the following lines:

    ssl start_tls

Then review the LDAP server and ensure TLS has been configured.

The ssl directive specifies whether to use ssl or not. If not specified it will default to no. It should be set to start_tls rather than doing LDAP over SSL.

CM-7

Configure Certificate Directives for LDAP Use of TLS

Ensure a copy of a trusted CA certificate has been placed in the file `/etc/pki/tls/CA/cacert.pem`. Configure LDAP to enforce TLS use and to trust certificates signed by that CA. First, edit the file `/etc/pam_ldap.conf`, and add or correct either of the following lines:

    tls_cacertdir /etc/pki/tls/CA

or

    tls_cacertfile /etc/pki/tls/CA/cacert.pem

Then review the LDAP server and ensure TLS has been configured.

The tls_cacertdir or tls_cacertfile directives are required when tls_checkpeer is configured (which is the default for openldap versions 2.1 and up). These directives define the path to the trust certificates signed by the site CA.

CM-7

Disable Postfix Network Listening

Edit the file `/etc/postfix/main.cf` to ensure that only the following `inet_interfaces` line appears:

    inet_interfaces = localhost

This ensures `postfix` accepts mail messages (such as cron job reports) from the local system only, and not from the network, which protects it from network attack.

AC-22

Configure SMTP Greeting Banner

Edit `/etc/postfix/main.cf`, and add or correct the following line, substituting some other wording for the banner information if you prefer:

    smtpd_banner = $myhostname ESMTP

The default greeting banner discloses that the listening mail process is Postfix. When remote mail senders connect to the MTA on port 25, they are greeted by an initial banner as part of the SMTP dialogue. This banner is necessary, but it frequently gives away too much information, including the MTA software which is in use, and sometimes also its version number. Remote mail senders do not need this information in order to send mail, so the banner should be changed to reveal only the hostname (which is already known and may be useful) and the word ESMTP, to indicate that the modern SMTP protocol variant is supported.

AU-13

Configure SMTP Greeting Banner

Edit `/etc/postfix/main.cf`, and add or correct the following line, substituting some other wording for the banner information if you prefer:

    smtpd_banner = $myhostname ESMTP

The default greeting banner discloses that the listening mail process is Postfix. When remote mail senders connect to the MTA on port 25, they are greeted by an initial banner as part of the SMTP dialogue. This banner is necessary, but it frequently gives away too much information, including the MTA software which is in use, and sometimes also its version number. Remote mail senders do not need this information in order to send mail, so the banner should be changed to reveal only the hostname (which is already known and may be useful) and the word ESMTP, to indicate that the modern SMTP protocol variant is supported.

CM-7

Uninstall Sendmail Package

Sendmail is not the default mail transfer agent and is not installed by default. The `sendmail` package can be removed with the following command:

    $ sudo yum erase sendmail

The sendmail software was not developed with security in mind and its design prevents it from being effectively contained by SELinux. Postfix should be used instead.

CM-7

Disable Avahi Server Software

The `avahi-daemon` service can be disabled with the following command:

    $ sudo chkconfig avahi-daemon off

Because the Avahi daemon service keeps an open network port, it is subject to network attacks. Its functionality is convenient but is only appropriate if the local network can be trusted.

CM-7

Check Avahi Responses' TTL Field

To make Avahi ignore packets unless the TTL field is 255, edit `/etc/avahi/avahi-daemon.conf` and ensure the following line appears in the `[server]` section:

    check-response-ttl=yes

This helps to ensure that only mDNS responses from the local network are processed, because the TTL field in a packet is decremented from its initial value of 255 whenever it is routed from one network to another. Although a properly-configured router or firewall should not allow mDNS packets into the local network at all, this option provides another check to ensure they are not permitted.

CM-7

Disable Avahi Publishing

To prevent Avahi from publishing its records, edit `/etc/avahi/avahi-daemon.conf` and ensure the following line appears in the `[publish]` section:

    disable-publishing=yes

This helps ensure that no record will be published by Avahi.

CM-7

Restrict Information Published by Avahi

If it is necessary to publish some information to the network, it should not be joined by any extraneous information, or by information supplied by a non-trusted source on the system. Prevent user applications from using Avahi to publish services by adding or correcting the following line in the `[publish]` section:

    disable-user-service-publishing=yes

Implement as many of the following lines as possible, to restrict the information published by Avahi.

    publish-addresses=no
    publish-hinfo=no
    publish-workstation=no
    publish-domain=no

Inspect the files in the directory `/etc/avahi/services/`. Unless there is an operational need to publish information about each of these services, delete the corresponding file.

These options prevent publishing attempts from succeeding, and can be applied even if publishing is disabled entirely via disable-publishing. Alternatively, these can be used to restrict the types of published information in the event that some information must be published.

CM-7

Serve Avahi Only via Required Protocol

If you are using only IPv4, edit `/etc/avahi/avahi-daemon.conf` and ensure the following line exists in the `[server]` section:

    use-ipv6=no

Similarly, if you are using only IPv6, disable IPv4 sockets with the line:

    use-ipv4=no

CM-7

Prevent Other Programs from Using Avahi's Port

To prevent other mDNS stacks from running, edit `/etc/avahi/avahi-daemon.conf` and ensure the following line appears in the `[server]` section:

    disallow-other-stacks=yes

This helps ensure that only Avahi is responsible for mDNS traffic coming from that port on the system.

AC-3

Disable X Windows Startup By Setting Runlevel

Setting the system's runlevel to 3 will prevent automatic startup of the X server. To do so, ensure the following line in `/etc/inittab` features a `3` as shown:

    id:3:initdefault:

Unnecessary services should be disabled to decrease the attack surface of the system.

AU-3(2)

Ensure Logs Sent To Remote Host

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 `loghost.example.com` 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:

    *.* @loghost.example.com

To use TCP for log message delivery:

    *.* @@loghost.example.com

To use RELP for log message delivery:

    *.* :omrelp:loghost.example.com

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.

AU-9

Ensure Logs Sent To Remote Host

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 `loghost.example.com` 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:

    *.* @loghost.example.com

To use TCP for log message delivery:

    *.* @@loghost.example.com

To use RELP for log message delivery:

    *.* :omrelp:loghost.example.com

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.

SI-11

Ensure System Log Files Have Correct Permissions

The file permissions for all log files written by `rsyslog` should be set to 600, or more restrictive. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's permissions:

    $ ls -l LOGFILE

If the permissions are not 600 or more restrictive, run the following command to correct this:

    $ sudo chmod 0600 LOGFILE

Log files can contain valuable information regarding system configuration. If the system log files are not protected unauthorized users could change the logged data, eliminating their forensic value.

AC-6

Ensure Log Files Are Owned By Appropriate User

The owner of all log files written by `rsyslog` should be root. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's owner:

    $ ls -l LOGFILE

If the owner is not `root`, run the following command to correct this:

    $ sudo chown root LOGFILE

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

SI-11

Ensure Log Files Are Owned By Appropriate User

The owner of all log files written by `rsyslog` should be root. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's owner:

    $ ls -l LOGFILE

If the owner is not `root`, run the following command to correct this:

    $ sudo chown root LOGFILE

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

AC-6

Ensure Log Files Are Owned By Appropriate Group

The group-owner of all log files written by `rsyslog` should be root. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's group owner:

    $ ls -l LOGFILE

If the owner is not `root`, run the following command to correct this:

    $ sudo chgrp root LOGFILE

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

SI-11

Ensure Log Files Are Owned By Appropriate Group

The group-owner of all log files written by `rsyslog` should be root. These log files are determined by the second part of each Rule line in `/etc/rsyslog.conf` and typically all appear in `/var/log`. For each log file LOGFILE referenced in `/etc/rsyslog.conf`, run the following command to inspect the file's group owner:

    $ ls -l LOGFILE

If the owner is not `root`, run the following command to correct this:

    $ sudo chgrp root LOGFILE

The log files generated by rsyslog contain valuable information regarding system configuration, user authentication, and other such information. Log files should be protected from unauthorized access.

AU-9

Enable rsyslog to Accept Messages via UDP, if Acting As Log Server

The `rsyslog` daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central log server, add the following lines to `/etc/rsyslog.conf` to enable reception of messages over UDP:

    $ModLoad imudp
    $UDPServerRun 514

Many devices, such as switches, routers, and other Unix-like systems, may only support the traditional syslog transmission over UDP. If the system must act as a log server, this enables it to receive their messages as well.

AU-9(2)

Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server

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 the following lines are not found in `/etc/rsyslog.conf`:

    $ModLoad imtcp
    $InputTCPServerRun port
    $ModLoad imudp
    $UDPServerRun port
    $ModLoad imrelp
    $InputRELPServerRun port

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.

AC-4

Ensure rsyslog Does Not Accept Remote Messages Unless Acting As Log Server

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 the following lines are not found in `/etc/rsyslog.conf`:

    $ModLoad imtcp
    $InputTCPServerRun port
    $ModLoad imudp
    $UDPServerRun port
    $ModLoad imrelp
    $InputRELPServerRun port

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.

AU-9

Enable rsyslog to Accept Messages via TCP, if Acting As Log Server

The `rsyslog` daemon should not accept remote messages unless the system acts as a log server. If the system needs to act as a central log server, add the following lines to `/etc/rsyslog.conf` to enable reception of messages over TCP:

    $ModLoad imtcp
    $InputTCPServerRun 514

If the system needs to act as a log server, this ensures that it can receive messages over a reliable TCP connection.

AU-9

Ensure Logrotate Runs Periodically

The `logrotate` utility allows for the automatic rotation of log files. The frequency of rotation is specified in `/etc/logrotate.conf`, which triggers a cron task. To configure logrotate to run daily, add or correct the following line in `/etc/logrotate.conf`:

    # rotate log files frequency
    daily

Log files that are not properly rotated run the risk of growing so large that they fill up the /var/log partition. Valuable logging information could be lost if the /var/log partition becomes full.

AU-12

Enable rsyslog Service

The `rsyslog` service provides syslog-style logging by default on Red Hat Enterprise Linux 6. The `rsyslog` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 rsyslog on

The `rsyslog` service must be running in order to provide logging services, which are essential to system administration.

AU-9(2)

Ensure rsyslog is Installed

Rsyslog is installed by default. The `rsyslog` package can be installed with the following command:

    $ sudo yum install rsyslog

The rsyslog package provides the rsyslog daemon, which provides system logging services.

AC-17

Install openswan or libreswan Package

The openswan and libreswan packages provide an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The `openswan` package can be installed with the following command:

    $ sudo yum install openswan

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

    $ sudo yum install libreswan

Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network.

MA-4

Install openswan or libreswan Package

The openswan and libreswan packages provide an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The `openswan` package can be installed with the following command:

    $ sudo yum install openswan

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

    $ sudo yum install libreswan

Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network.

SC-8

Install openswan or libreswan Package

The openswan and libreswan packages provide an implementation of IPsec and IKE, which permits the creation of secure tunnels over untrusted networks. The `openswan` package can be installed with the following command:

    $ sudo yum install openswan

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

    $ sudo yum install libreswan

Providing the ability for remote users or systems to initiate a secure VPN connection protects information when it is transmitted over a wide area network.

CM-7

Set Default iptables Policy for Forwarded Packets

To set the default policy to DROP (instead of ACCEPT) for the built-in FORWARD chain which processes packets that will be forwarded from one interface to another, add or correct the following line in `/etc/sysconfig/iptables`:

    :FORWARD DROP [0:0]

In `iptables`, the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to `DROP` implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.

CM-7

Set Default iptables Policy for Incoming Packets

To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in `/etc/sysconfig/iptables`:

    :INPUT DROP [0:0]

In `iptables` the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to `DROP` implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.

AC-4

Verify ip6tables Enabled if Using IPv6

The `ip6tables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 ip6tables on

The `ip6tables` service provides the system's host-based firewalling capability for IPv6 and ICMPv6.

CA-3(c)

Verify ip6tables Enabled if Using IPv6

The `ip6tables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 ip6tables on

The `ip6tables` service provides the system's host-based firewalling capability for IPv6 and ICMPv6.

CM-7

Verify ip6tables Enabled if Using IPv6

The `ip6tables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 ip6tables on

The `ip6tables` service provides the system's host-based firewalling capability for IPv6 and ICMPv6.

CM-7

Set Default ip6tables Policy for Incoming Packets

To set the default policy to DROP (instead of ACCEPT) for the built-in INPUT chain which processes incoming packets, add or correct the following line in `/etc/sysconfig/ip6tables`:

    :INPUT DROP [0:0]

If changes were required, reload the ip6tables rules:

    $ sudo service ip6tables reload

In `ip6tables`, the default policy is applied only after all the applicable rules in the table are examined for a match. Setting the default policy to `DROP` implements proper design for a firewall, i.e. any packets which are not explicitly permitted should not be accepted.

AC-4

Verify iptables Enabled

The `iptables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 iptables on

The `iptables` service provides the system's host-based firewalling capability for IPv4 and ICMP.

CA-3(c)

Verify iptables Enabled

The `iptables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 iptables on

The `iptables` service provides the system's host-based firewalling capability for IPv4 and ICMP.

CM-7

Verify iptables Enabled

The `iptables` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 iptables on

The `iptables` service provides the system's host-based firewalling capability for IPv4 and ICMP.

AC-4

Configure Kernel Parameter for Accepting Source-Routed Packets for Interfaces By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.default.accept_source_route = 0

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.

AC-4

Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.all.accept_source_route = 0

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.

CM-7

Disable Kernel Parameter for IPv6 Forwarding

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.all.forwarding = 0

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.

SC-5

Disable Kernel Parameter for IPv6 Forwarding

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.all.forwarding = 0

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.

CM-7

Configure Accepting IPv6 Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.all.accept_redirects = 0

An illicit ICMP redirect message could result in a man-in-the-middle attack.

CM-7

Configure Accepting IPv6 Router Advertisements

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.default.accept_ra = 0

An illicit router advertisement message could result in a man-in-the-middle attack.

CM-7

Configure Accepting IPv6 Router Advertisements

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.all.accept_ra = 0

An illicit router advertisement message could result in a man-in-the-middle attack.

CM-7

Configure Accepting IPv6 Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv6.conf.default.accept_redirects = 0

An illicit ICMP redirect message could result in a man-in-the-middle attack.

CM-6(b)

Manually Assign IPv6 Router Address

Edit the file `/etc/sysconfig/network-scripts/ifcfg-interface`, and add or correct the following line (substituting your gateway IP as appropriate):

    IPV6_DEFAULTGW=2001:0DB8::0001

Router addresses should be manually set and not accepted via any auto-configuration or router advertisement.

CM-6(b)

Manually Assign Global IPv6 Address

To manually assign an IP address for an interface, edit the file `/etc/sysconfig/network-scripts/ifcfg-interface`. Add or correct the following line (substituting the correct IPv6 address):

    IPV6ADDR=2001:0DB8::ABCD/64

Manually assigning an IP address is preferable to accepting one from routers or from the network otherwise. The example address here is an IPv6 address reserved for documentation purposes, as defined by RFC3849.

CM-6(b)

Use Privacy Extensions for Address

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.

CM-7

Disable Support for RPC IPv6

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     -       -

CM-7

Disable IPv6 Networking Support Automatic Loading

To prevent the IPv6 kernel module (`ipv6`) from binding to the IPv6 networking stack, add the following line to `/etc/modprobe.d/disabled.conf` (or another file in `/etc/modprobe.d`):

    options ipv6 disable=1

This permits the IPv6 module to be loaded (and thus satisfy other modules that depend on it), while disabling support for the IPv6 protocol.

Any unnecessary network stacks - including IPv6 - should be disabled, to reduce the vulnerability to exploitation.

AC-4

Configure Kernel Parameter for Accepting Source-Routed Packets By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter for Accepting Source-Routed Packets By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting Source-Routed Packets By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

SC-7

Configure Kernel Parameter for Accepting Source-Routed Packets By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter to Ignore Bogus ICMP Error Responses

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.icmp_ignore_bogus_error_responses = 1

Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.

SC-5

Configure Kernel Parameter to Ignore Bogus ICMP Error Responses

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.icmp_ignore_bogus_error_responses = 1

Ignoring bogus ICMP error responses reduces log size, although some activity would not be logged.

AC-4

Configure Kernel Parameter for Accepting ICMP Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_redirects = 0

This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter for Accepting ICMP Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_redirects = 0

This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting ICMP Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_redirects = 0

This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

SC-7

Configure Kernel Parameter for Accepting ICMP Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.accept_redirects = 0

This feature of the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

AC-4

Configure Kernel Parameter to Use Reverse Path Filtering by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.rp_filter = 1

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.

SC-5

Configure Kernel Parameter to Use Reverse Path Filtering by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.rp_filter = 1

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.

SC-7

Configure Kernel Parameter to Use Reverse Path Filtering by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.rp_filter = 1

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.

AC-4

Configure Kernel Parameter for Accepting Secure Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter for Accepting Secure Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting Secure Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

AC-4

Configure Kernel Parameter to Use TCP Syncookies

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.tcp_syncookies = 1

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.

SC-5(2)

Configure Kernel Parameter to Use TCP Syncookies

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.tcp_syncookies = 1

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.

SC-5(3)

Configure Kernel Parameter to Use TCP Syncookies

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.tcp_syncookies = 1

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.

CM-7

Configure Kernel Parameter for Accepting ICMP Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.accept_redirects = 0

Accepting ICMP redirects has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting ICMP Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.accept_redirects = 0

Accepting ICMP redirects has few legitimate uses. It should be disabled unless it is absolutely required.

AC-3(10)

Configure Kernel Parameter to Log Martian Packets

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.log_martians = 1

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.

CM-7

Configure Kernel Parameter to Log Martian Packets

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.log_martians = 1

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.

SC-5(3)

Configure Kernel Parameter to Log Martian Packets

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.log_martians = 1

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.

AC-4

Configure Kernel Parameter to Use Reverse Path Filtering for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.rp_filter = 1

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.

SC-5

Configure Kernel Parameter to Use Reverse Path Filtering for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.rp_filter = 1

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.

SC-7

Configure Kernel Parameter to Use Reverse Path Filtering for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.rp_filter = 1

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.

CM-7

Configure Kernel Parameter to Ignore ICMP Broadcast Echo Requests

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.icmp_echo_ignore_broadcasts = 1

Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.

SC-5

Configure Kernel Parameter to Ignore ICMP Broadcast Echo Requests

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.icmp_echo_ignore_broadcasts = 1

Ignoring ICMP echo requests (pings) sent to broadcast or multicast addresses makes the system slightly more difficult to enumerate on the network.

AC-4

Configure Kernel Parameter for Accepting Secure Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter for Accepting Secure Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting Secure Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

SC-7

Configure Kernel Parameter for Accepting Secure Redirects By Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.secure_redirects = 0

Accepting "secure" ICMP redirects (from those gateways listed as default gateways) has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

SC-5

Configure Kernel Parameter for Accepting Source-Routed Packets for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.accept_source_route = 0

Accepting source-routed packets in the IPv4 protocol has few legitimate uses. It should be disabled unless it is absolutely required.

CM-7

Disable Kernel Parameter for IP Forwarding

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.ip_forward = 0

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.

SC-5

Disable Kernel Parameter for IP Forwarding

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.ip_forward = 0

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.

CM-7

Disable Kernel Parameter for Sending ICMP Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

SC-5(1)

Disable Kernel Parameter for Sending ICMP Redirects for All Interfaces

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.all.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

AC-4

Disable Kernel Parameter for Sending ICMP Redirects by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

CM-7

Disable Kernel Parameter for Sending ICMP Redirects by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

SC-5

Disable Kernel Parameter for Sending ICMP Redirects by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

SC-7

Disable Kernel Parameter for Sending ICMP Redirects by Default

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    net.ipv4.conf.default.send_redirects = 0

Sending ICMP redirects permits the system to instruct other systems to update their routing information. The ability to send ICMP redirects is only appropriate for systems acting as routers.

CM-7

Disable DCCP Support

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 a file in the directory `/etc/modprobe.d`:

    install dccp /bin/true

Disabling DCCP protects the system against exploitation of any flaws in its implementation.

CM-7

Disable RDS Support

The Reliable Datagram Sockets (RDS) protocol is a transport layer protocol designed to provide reliable high- bandwidth, low-latency communications between nodes in a cluster. To configure the system to prevent the `rds` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install rds /bin/true

Disabling RDS protects the system against exploitation of any flaws in its implementation.

CM-7

Disable SCTP Support

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 a file in the directory `/etc/modprobe.d`:

    install sctp /bin/true

Disabling SCTP protects the system against exploitation of any flaws in its implementation.

CM-7

Disable TIPC Support

The Transparent Inter-Process Communication (TIPC) protocol is designed to provide communications between nodes in a cluster. To configure the system to prevent the `tipc` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install tipc /bin/true

Disabling TIPC protects the system against exploitation of any flaws in its implementation.

AC-18(a)

Disable Bluetooth Kernel Modules

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

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

AC-18(d)

Disable Bluetooth Kernel Modules

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

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

AC-18(3)

Disable Bluetooth Kernel Modules

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

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

CM-7

Disable Bluetooth Kernel Modules

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

If Bluetooth functionality must be disabled, preventing the kernel from loading the kernel module provides an additional safeguard against its activation.

AC-18(a)

Disable WiFi or Bluetooth in BIOS

Some systems that include built-in wireless support offer the ability to disable the device through the BIOS. This is system-specific; consult your hardware manual or explore the BIOS setup during boot.

Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.

AC-18(d)

Disable WiFi or Bluetooth in BIOS

Some systems that include built-in wireless support offer the ability to disable the device through the BIOS. This is system-specific; consult your hardware manual or explore the BIOS setup during boot.

Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.

AC-18(3)

Disable WiFi or Bluetooth in BIOS

Some systems that include built-in wireless support offer the ability to disable the device through the BIOS. This is system-specific; consult your hardware manual or explore the BIOS setup during boot.

Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.

CM-7

Disable WiFi or Bluetooth in BIOS

Some systems that include built-in wireless support offer the ability to disable the device through the BIOS. This is system-specific; consult your hardware manual or explore the BIOS setup during boot.

Disabling wireless support in the BIOS prevents easy activation of the wireless interface, generally requiring administrators to reboot the system first.

AC-18(a)

Disable Bluetooth Service

The `bluetooth` service can be disabled with the following command:

    $ sudo chkconfig bluetooth off

    $ sudo service bluetooth stop

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.

AC-18(d)

Disable Bluetooth Service

The `bluetooth` service can be disabled with the following command:

    $ sudo chkconfig bluetooth off

    $ sudo service bluetooth stop

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.

AC-18(3)

Disable Bluetooth Service

The `bluetooth` service can be disabled with the following command:

    $ sudo chkconfig bluetooth off

    $ sudo service bluetooth stop

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.

CM-7

Disable Bluetooth Service

The `bluetooth` service can be disabled with the following command:

    $ sudo chkconfig bluetooth off

    $ sudo service bluetooth stop

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.

AC-18(a)

Deactivate Wireless Network Interfaces

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.
First, identify the interfaces available with the command:

    $ ifconfig -a

Additionally, the following command may be used to determine whether wireless support is included for a particular interface, though this may not always be a clear indicator:

    $ iwconfig

After identifying any wireless interfaces (which may have names like `wlan0`, `ath0`, `wifi0`, `em1` or `eth0`), deactivate the interface with the command:

    $ sudo ifdown interface

These changes will only last until the next reboot. To disable the interface for future boots, remove the appropriate interface file from `/etc/sysconfig/network-scripts`:

    $ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface

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.

AC-18(d)

Deactivate Wireless Network Interfaces

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.
First, identify the interfaces available with the command:

    $ ifconfig -a

Additionally, the following command may be used to determine whether wireless support is included for a particular interface, though this may not always be a clear indicator:

    $ iwconfig

After identifying any wireless interfaces (which may have names like `wlan0`, `ath0`, `wifi0`, `em1` or `eth0`), deactivate the interface with the command:

    $ sudo ifdown interface

These changes will only last until the next reboot. To disable the interface for future boots, remove the appropriate interface file from `/etc/sysconfig/network-scripts`:

    $ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface

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.

AC-18(3)

Deactivate Wireless Network Interfaces

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.
First, identify the interfaces available with the command:

    $ ifconfig -a

Additionally, the following command may be used to determine whether wireless support is included for a particular interface, though this may not always be a clear indicator:

    $ iwconfig

After identifying any wireless interfaces (which may have names like `wlan0`, `ath0`, `wifi0`, `em1` or `eth0`), deactivate the interface with the command:

    $ sudo ifdown interface

These changes will only last until the next reboot. To disable the interface for future boots, remove the appropriate interface file from `/etc/sysconfig/network-scripts`:

    $ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface

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.

CM-7

Deactivate Wireless Network Interfaces

Deactivating wireless network interfaces should prevent normal usage of the wireless capability.
First, identify the interfaces available with the command:

    $ ifconfig -a

Additionally, the following command may be used to determine whether wireless support is included for a particular interface, though this may not always be a clear indicator:

    $ iwconfig

After identifying any wireless interfaces (which may have names like `wlan0`, `ath0`, `wifi0`, `em1` or `eth0`), deactivate the interface with the command:

    $ sudo ifdown interface

These changes will only last until the next reboot. To disable the interface for future boots, remove the appropriate interface file from `/etc/sysconfig/network-scripts`:

    $ sudo rm /etc/sysconfig/network-scripts/ifcfg-interface

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.

CM-7

Ensure System is Not Acting as a Network Sniffer

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

If any results are returned, then a sniffing process (such as tcpdump or Wireshark) is likely to be using the interface and this should be investigated.

MA-3

Ensure System is Not Acting as a Network Sniffer

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

If any results are returned, then a sniffing process (such as tcpdump or Wireshark) is likely to be using the interface and this should be investigated.

CM-7

Disable Zeroconf Networking

Zeroconf networking allows the system to assign itself an IP address and engage in IP communication without a statically-assigned address or even a DHCP server. Automatic address assignment via Zeroconf (or DHCP) is not recommended. To disable Zeroconf automatic route assignment in the 169.254.0.0 subnet, add or correct the following line in `/etc/sysconfig/network`:

    NOZEROCONF=yes

Zeroconf addresses are in the network 169.254.0.0. The networking scripts add entries to the system's routing table for these addresses. Zeroconf address assignment commonly occurs when the system is configured to use DHCP but fails to receive an address assignment from the DHCP server.

AC-3

Configure SELinux Policy

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=

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

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 ``.

AC-3(3)

Configure SELinux Policy

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=

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

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 ``.

AC-4

Configure SELinux Policy

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=

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

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 ``.

AC-6

Configure SELinux Policy

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=

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

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 ``.

AU-9

Configure SELinux Policy

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=

Other policies, such as `mls`, provide additional security labeling and greater confinement but are not compatible with many general-purpose use cases.

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 ``.

AC-3

Ensure SELinux Not Disabled in /etc/grub.conf

SELinux can be disabled at boot time by an argument in `/etc/grub.conf`. Remove any instances of `selinux=0` from the kernel arguments in that file to prevent SELinux from being disabled at boot.

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.

AC-3(3)

Ensure SELinux Not Disabled in /etc/grub.conf

SELinux can be disabled at boot time by an argument in `/etc/grub.conf`. Remove any instances of `selinux=0` from the kernel arguments in that file to prevent SELinux from being disabled at boot.

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.

AC-6

Ensure SELinux Not Disabled in /etc/grub.conf

SELinux can be disabled at boot time by an argument in `/etc/grub.conf`. Remove any instances of `selinux=0` from the kernel arguments in that file to prevent SELinux from being disabled at boot.

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.

AU-9

Ensure SELinux Not Disabled in /etc/grub.conf

SELinux can be disabled at boot time by an argument in `/etc/grub.conf`. Remove any instances of `selinux=0` from the kernel arguments in that file to prevent SELinux from being disabled at boot.

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.

AC-6

Ensure No Daemons are Unconfined by SELinux

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 `initrc_t` context.
To check for unconfined daemons, run the following command:

    $ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'

It should produce no output in a well-configured system.

Daemons which run with the `initrc_t` context may cause AVC denials, or allow privileges that the daemon does not require.

AU-9

Ensure No Daemons are Unconfined by SELinux

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 `initrc_t` context.
To check for unconfined daemons, run the following command:

    $ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'

It should produce no output in a well-configured system.

Daemons which run with the `initrc_t` context may cause AVC denials, or allow privileges that the daemon does not require.

CM-7

Ensure No Daemons are Unconfined by SELinux

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 `initrc_t` context.
To check for unconfined daemons, run the following command:

    $ sudo ps -eZ | egrep "initrc" | egrep -vw "tr|ps|egrep|bash|awk" | tr ':' ' ' | awk '{ print $NF }'

It should produce no output in a well-configured system.

Daemons which run with the `initrc_t` context may cause AVC denials, or allow privileges that the daemon does not require.

AC-6

Ensure No Device Files are Unknown to SELinux

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`, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.

If a device file carries the SELinux type `device_t`, then SELinux cannot properly restrict access to the device file.

AU-9

Ensure No Device Files are Unknown to SELinux

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`, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.

If a device file carries the SELinux type `device_t`, then SELinux cannot properly restrict access to the device file.

CM-7

Ensure No Device Files are Unknown to SELinux

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`, report the bug so that policy can be corrected. Supply information about what the device is and what programs use it.

If a device file carries the SELinux type `device_t`, then SELinux cannot properly restrict access to the device file.

AC-3

Ensure SELinux State is Enforcing

The SELinux state should be set to `` 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=

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.

AC-3(3)

Ensure SELinux State is Enforcing

The SELinux state should be set to `` 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=

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.

AC-4

Ensure SELinux State is Enforcing

The SELinux state should be set to `` 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=

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.

AC-6

Ensure SELinux State is Enforcing

The SELinux state should be set to `` 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=

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.

AU-9

Ensure SELinux State is Enforcing

The SELinux state should be set to `` 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=

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.

AC-3

Enable the SELinux Context Restoration Service (restorecond)

The `restorecond` service utilizes `inotify` to look for the creation of new files listed in the `/etc/selinux/restorecond.conf` configuration file. When a file is created, `restorecond` ensures the file receives the proper SELinux security context. The `restorecond` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 restorecond on

The `restorecond` service helps ensure that the default SELinux file context is applied to files. This allows automatic correction of file contexts created by some programs.

AC-3(3)

Enable the SELinux Context Restoration Service (restorecond)

The `restorecond` service utilizes `inotify` to look for the creation of new files listed in the `/etc/selinux/restorecond.conf` configuration file. When a file is created, `restorecond` ensures the file receives the proper SELinux security context. The `restorecond` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 restorecond on

The `restorecond` service helps ensure that the default SELinux file context is applied to files. This allows automatic correction of file contexts created by some programs.

AC-4

Enable the SELinux Context Restoration Service (restorecond)

The `restorecond` service utilizes `inotify` to look for the creation of new files listed in the `/etc/selinux/restorecond.conf` configuration file. When a file is created, `restorecond` ensures the file receives the proper SELinux security context. The `restorecond` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 restorecond on

The `restorecond` service helps ensure that the default SELinux file context is applied to files. This allows automatic correction of file contexts created by some programs.

AC-6

Enable the SELinux Context Restoration Service (restorecond)

The `restorecond` service utilizes `inotify` to look for the creation of new files listed in the `/etc/selinux/restorecond.conf` configuration file. When a file is created, `restorecond` ensures the file receives the proper SELinux security context. The `restorecond` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 restorecond on

The `restorecond` service helps ensure that the default SELinux file context is applied to files. This allows automatic correction of file contexts created by some programs.

AU-9

Enable the SELinux Context Restoration Service (restorecond)

The `restorecond` service utilizes `inotify` to look for the creation of new files listed in the `/etc/selinux/restorecond.conf` configuration file. When a file is created, `restorecond` ensures the file receives the proper SELinux security context. The `restorecond` service can be enabled with the following command:

    $ sudo chkconfig --level 2345 restorecond on

The `restorecond` service helps ensure that the default SELinux file context is applied to files. This allows automatic correction of file contexts created by some programs.

AC-2

Ensure that System Accounts Do Not Run a Shell Upon Login

Some accounts are not associated with a human user of the system, and exist to perform some administrative function. Should an attacker be able to log into these accounts, they should not be granted access to a shell.
The login shell for each local account is stored in the last field of each line in `/etc/passwd`. System accounts are those user accounts with a user ID less than UID_MIN, where value of the UID_MIN directive is set in /etc/login.defs configuration file. In the default configuration UID_MIN is set to 500, thus system accounts are those user accounts with a user ID less than 500. The user ID is stored in the third field. If any system account SYSACCT (other than root) has a login shell, disable it with the command:

    $ sudo usermod -s /sbin/nologin SYSACCT

Ensuring shells are not given to system accounts upon login makes it more difficult for attackers to make use of system accounts.

SA-8

Root Path Must Be Vendor Default

Assuming root shell is bash, edit the following files:

    ~/.profile

    ~/.bashrc

Change any `PATH` variables to the vendor default for root and remove any empty `PATH` entries or references to relative paths.

The root account's executable search path must be the vendor default, and must contain only absolute paths.

IA-2(1)

Direct root Logins Not Allowed

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 his machine as root via Telnet, which sends the password in plain text over the network. By default, Red Hat Enteprise Linux's `/etc/securetty` file only allows the root user to login at the console physically attached to the machine. 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

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.

AC-6(2)

Restrict Virtual Console Root Logins

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

Preventing direct root login to virtual console devices helps ensure accountability for actions taken on the system using the root account.

AC-6(2)

Restrict Serial Port Root Logins

To restrict root logins on serial ports, ensure lines of this form do not appear in `/etc/securetty`:

    ttyS0
    ttyS1

Preventing direct root login to serial port interfaces helps ensure accountability for actions taken on the systems using the root account.

AC-6

Verify Only Root Has UID 0

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.

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.

IA-2(1)

Verify Only Root Has UID 0

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.

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.

IA-5(b)

Prevent Log In to Accounts With Empty Password

If an account is configured for password authentication but does not have an assigned password, it may be possible to log onto the account without authentication. Remove any instances of the `nullok` option in `/etc/pam.d/system-auth` to prevent logins with empty passwords.

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.

IA-5(c)

Prevent Log In to Accounts With Empty Password

If an account is configured for password authentication but does not have an assigned password, it may be possible to log onto the account without authentication. Remove any instances of the `nullok` option in `/etc/pam.d/system-auth` to prevent logins with empty passwords.

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.

IA-5(1)(a)

Prevent Log In to Accounts With Empty Password

If an account is configured for password authentication but does not have an assigned password, it may be possible to log onto the account without authentication. Remove any instances of the `nullok` option in `/etc/pam.d/system-auth` to prevent logins with empty passwords.

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.

IA-5(h)

Verify No netrc Files Exist

The `.netrc` files contain login information used to auto-login into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any `.netrc` files should be removed.

Unencrypted passwords for remote FTP servers may be stored in `.netrc` files. DoD policy requires passwords be encrypted in storage and not used in access scripts.

AC-3

Verify No netrc Files Exist

The `.netrc` files contain login information used to auto-login into FTP servers and reside in the user's home directory. These files may contain unencrypted passwords to remote FTP servers making them susceptible to access by unauthorized users and should not be used. Any `.netrc` files should be removed.

Unencrypted passwords for remote FTP servers may be stored in `.netrc` files. DoD policy requires passwords be encrypted in storage and not used in access scripts.

IA-5(h)

Verify All Account Password Hashes are Shadowed

If any password hashes are stored in `/etc/passwd` (in the second field, instead of an `x`), 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.

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.

IA-5(f)

Set Password Minimum Length in login.defs

To specify password length requirements for new accounts, edit the file `/etc/login.defs` and add or correct the following lines:

    PASS_MIN_LEN

As of the DISA Red Hat 6 STIG - Ver 1, Rel 13 (28-OCT-2016), the DoD requirement is now `15`. The FISMA requirement is `12`. If a program consults `/etc/login.defs` and also another PAM module (such as `pam_cracklib`) during a password change operation, then the most restrictive must be satisfied. See PAM section for more information about enforcing password quality requirements.

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.

IA-5(1)(a)

Set Password Minimum Length in login.defs

To specify password length requirements for new accounts, edit the file `/etc/login.defs` and add or correct the following lines:

    PASS_MIN_LEN

As of the DISA Red Hat 6 STIG - Ver 1, Rel 13 (28-OCT-2016), the DoD requirement is now `15`. The FISMA requirement is `12`. If a program consults `/etc/login.defs` and also another PAM module (such as `pam_cracklib`) during a password change operation, then the most restrictive must be satisfied. See PAM section for more information about enforcing password quality requirements.

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.

IA-5(f)

Set Password Minimum Age

To specify password minimum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MIN_DAYS

A value of 1 day is considered sufficient for many environments. The DoD requirement is 1.

Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.

IA-5(1)(d)

Set Password Minimum Age

To specify password minimum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MIN_DAYS

A value of 1 day is considered sufficient for many environments. The DoD requirement is 1.

Setting the minimum password age protects against users cycling back to a favorite password after satisfying the password reuse requirement.

IA-5(f)

Set Password Maximum Age

To specify password maximum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MAX_DAYS

A value of 180 days is sufficient for many environments. The DoD requirement is 60.

Setting the password maximum age ensures users are required to periodically change their passwords. This could possibly decrease the utility of a stolen password. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

IA-5(g)

Set Password Maximum Age

To specify password maximum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MAX_DAYS

A value of 180 days is sufficient for many environments. The DoD requirement is 60.

Setting the password maximum age ensures users are required to periodically change their passwords. This could possibly decrease the utility of a stolen password. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

IA-5(1)(d)

Set Password Maximum Age

To specify password maximum age for new accounts, edit the file `/etc/login.defs` and add or correct the following line:

    PASS_MAX_DAYS

A value of 180 days is sufficient for many environments. The DoD requirement is 60.

Setting the password maximum age ensures users are required to periodically change their passwords. This could possibly decrease the utility of a stolen password. Requiring shorter password lifetimes increases the risk of users writing down the password in a convenient location subject to physical compromise.

AC-2(2)

Set Password Warning Age

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

The DoD requirement is 7.

Setting the password warning age enables users to make the change at a practical time.

IA-5(f)

Set Password Warning Age

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

The DoD requirement is 7.

Setting the password warning age enables users to make the change at a practical time.

AC-2(2)

Set Account Expiration Following Inactivity

To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following lines in `/etc/default/useradd`, substituting `NUM_DAYS` appropriately:

    INACTIVE=

A value of 35 is recommended. If a password is currently on the verge of expiration, then 35 days remain until the account is automatically disabled. However, if the password will not expire for another 60 days, then 95 days could elapse until the account would be automatically disabled. See the `useradd` man page for more information. Determining the inactivity timeout must be done with careful consideration of the length of a "normal" period of inactivity for users in the particular environment. Setting the timeout too low incurs support costs and also has the potential to impact availability of the system to legitimate users.

Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.

AC-2(3)

Set Account Expiration Following Inactivity

To specify the number of days after a password expires (which signifies inactivity) until an account is permanently disabled, add or correct the following lines in `/etc/default/useradd`, substituting `NUM_DAYS` appropriately:

    INACTIVE=

A value of 35 is recommended. If a password is currently on the verge of expiration, then 35 days remain until the account is automatically disabled. However, if the password will not expire for another 60 days, then 95 days could elapse until the account would be automatically disabled. See the `useradd` man page for more information. Determining the inactivity timeout must be done with careful consideration of the length of a "normal" period of inactivity for users in the particular environment. Setting the timeout too low incurs support costs and also has the potential to impact availability of the system to legitimate users.

Disabling inactive accounts ensures that accounts which may not have been responsibly removed are not available to attackers who may have compromised their credentials.

AC-2(2)

Assign Expiration Date to Temporary Accounts

In the event temporary or emergency accounts are required, configure the system to terminate them after a documented time period. For every temporary and emergency account, run the following command to set an expiration date on it, substituting `USER` and `YYYY-MM-DD` appropriately:

    $ sudo chage -E YYYY-MM-DD USER

`YYYY-MM-DD` indicates the documented expiration date for the account.

When temporary and emergency accounts are created, there is a risk they may remain in place and active after the need for them no longer exists. Account expiration greatly reduces the risk of accounts being misused or hijacked.

AC-2(3)

Assign Expiration Date to Temporary Accounts

In the event temporary or emergency accounts are required, configure the system to terminate them after a documented time period. For every temporary and emergency account, run the following command to set an expiration date on it, substituting `USER` and `YYYY-MM-DD` appropriately:

    $ sudo chage -E YYYY-MM-DD USER

`YYYY-MM-DD` indicates the documented expiration date for the account.

When temporary and emergency accounts are created, there is a risk they may remain in place and active after the need for them no longer exists. Account expiration greatly reduces the risk of accounts being misused or hijacked.

AC-6(7)

Verify /etc/grub.conf Group Ownership

The file `/etc/grub.conf` should be group-owned by the `root` group to prevent destruction or modification of the file. To properly set the group owner of `/etc/grub.conf`, run the command:

    $ sudo chgrp root /etc/grub.conf

The `root` group is a highly-privileged group. Furthermore, the group-owner of this file should not have any access privileges anyway.

AC-6(7)

Verify /etc/grub.conf User Ownership

The file `/etc/grub.conf` should be owned by the `root` user to prevent destruction or modification of the file. To properly set the owner of `/etc/grub.conf`, run the command:

    $ sudo chown root /etc/grub.conf

Only root should be able to modify important boot parameters.

IA-2(1)

Set Boot Loader Password

The grub boot loader should have password protection enabled to protect boot-time settings. To do so, select a password and then generate a hash from it by running the following command:

    $ grub-crypt --sha-512

When prompted to enter a password, insert the following line into `/etc/grub.conf` immediately after the header comments. (Use the output from `grub-crypt` as the value of password-hash):

    password --encrypted password-hash

NOTE: To meet FISMA Moderate, the bootloader password MUST differ from the root password.

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.

IA-5(e) AC-3

Set Boot Loader Password

The grub boot loader should have password protection enabled to protect boot-time settings. To do so, select a password and then generate a hash from it by running the following command:

    $ grub-crypt --sha-512

When prompted to enter a password, insert the following line into `/etc/grub.conf` immediately after the header comments. (Use the output from `grub-crypt` as the value of password-hash):

    password --encrypted password-hash

NOTE: To meet FISMA Moderate, the bootloader password MUST differ from the root password.

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.

AC-6(7)

Verify /boot/grub/grub.conf Permissions

File permissions for `/boot/grub/grub.conf` should be set to 600, which is the default. To properly set the permissions of `/boot/grub/grub.conf`, run the command:

    $ sudo chmod 600 /boot/grub/grub.conf

Proper permissions ensure that only the root user can modify important boot parameters.

SC-2

Disable Interactive Boot

To disable the ability for users to perform interactive startups, perform both of the following:

1. Edit the file `/etc/sysconfig/init`. Add or correct the line:

       PROMPT=no

2. Inspect the kernel boot arguments (which follow the word `kernel`) in `/etc/grub.conf` and ensure the `confirm` argument is not present.

Both the `PROMPT` option of the `/etc/sysconfig/init` file and the `confirm` kernel boot argument of the `/etc/grub.conf` file allow the console user to perform an interactive system startup, in which it is possible to select the set of services which are started on boot.

Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.

AC-3

Disable Interactive Boot

To disable the ability for users to perform interactive startups, perform both of the following:

1. Edit the file `/etc/sysconfig/init`. Add or correct the line:

       PROMPT=no

2. Inspect the kernel boot arguments (which follow the word `kernel`) in `/etc/grub.conf` and ensure the `confirm` argument is not present.

Both the `PROMPT` option of the `/etc/sysconfig/init` file and the `confirm` kernel boot argument of the `/etc/grub.conf` file allow the console user to perform an interactive system startup, in which it is possible to select the set of services which are started on boot.

Using interactive boot, the console user could disable auditing, firewalls, or other services, weakening system security.

IA-2(1)

Require Authentication for Single User Mode

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, no authentication is performed if single-user mode is selected.
To require entry of the root password even if the system is started in single-user mode, add or correct the following line in the file `/etc/sysconfig/init`:

    SINGLE=/sbin/sulogin

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.

AC-3

Require Authentication for Single User Mode

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, no authentication is performed if single-user mode is selected.
To require entry of the root password even if the system is started in single-user mode, add or correct the following line in the file `/etc/sysconfig/init`:

    SINGLE=/sbin/sulogin

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.

CM-6(b)

Ensure that Root's Path Does Not Include Relative Paths or Null Directories

Ensure that none of the directories in root's path is equal to a single `.` character, or that it contains any instances that lead to relative path traversal, such as `..` or beginning a path without the slash (`/`) character. Also ensure that there are no "empty" elements in the path, such as in these examples:

    PATH=:/bin
    PATH=/bin:
    PATH=/bin::/sbin

These empty elements have the same effect as a single `.` character.

Including these entries increases the risk that root could execute code from an untrusted location.

CM-6(b)

Ensure that Root's Path Does Not Include World or Group-Writable Directories

For each element in root's path, run:

    $ sudo ls -ld DIR

and ensure that write permissions are disabled for group and other.

Such entries increase the risk that root could execute code provided by unprivileged users, and potentially malicious code.

SA-8

Ensure the Default Umask is Set Correctly in login.defs

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

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.

SA-8

Ensure the Default Bash Umask is Set Correctly

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

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.

SA-8

Ensure the Default C Shell Umask is Set Correctly

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

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.

SA-8

Ensure the Default Umask is Set Correctly in /etc/profile

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

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.

AC-6(7)

Ensure that User Home Directories are not Group-Writable or World-Readable

For each human user of the system, view the permissions of the user's home directory:

    $ sudo ls -ld /home/USER

Ensure that the directory is not group-writable and that it is not world-readable. If necessary, repair the permissions:

    $ sudo chmod g-w /home/USER
    $ sudo chmod o-rwx /home/USER

User home directories contain many configuration files which affect the behavior of a user's account. No user should ever have write permission to another user's home directory. Group shared directories can be configured in sub-directories or elsewhere in the filesystem if they are needed. Typically, user home directories should not be world-readable, as it would disclose file names to other users. If a subset of users need read access to one another's home directories, this can be provided using groups or ACLs.

AC-10

Limit the Number of Concurrent Login Sessions Allowed Per User

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. The DoD requirement is 10. To set the number of concurrent sessions per user add the following line in `/etc/security/limits.conf`:

    * hard maxlogins

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.

AC-8(a)

Enable GUI Warning Banner

To enable displaying a login warning banner in the GNOME Display Manager's login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gdm/simple-greeter/banner_message_enable true

To display a banner, this setting must be enabled and then banner text must also be set.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(b)

Enable GUI Warning Banner

To enable displaying a login warning banner in the GNOME Display Manager's login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gdm/simple-greeter/banner_message_enable true

To display a banner, this setting must be enabled and then banner text must also be set.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(c)

Enable GUI Warning Banner

To enable displaying a login warning banner in the GNOME Display Manager's login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gdm/simple-greeter/banner_message_enable true

To display a banner, this setting must be enabled and then banner text must also be set.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(a)

Set GUI Warning Banner Text

To set the text shown by the GNOME Display Manager in the login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gdm/simple-greeter/banner_message_text \
      "Text of the warning banner here"

When entering a warning banner that spans several lines, remember to begin and end the string with `"`. This command writes directly either to the `/etc/gconf/gconf.xml.mandatory/%gconf-tree.xml` if it exists or to the file `/etc/gconf/gconf.xml.mandatory/apps/gdm/simple-greeter/%gconf.xml`. Either of these files can later be edited directly if necessary.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(b)

Set GUI Warning Banner Text

To set the text shown by the GNOME Display Manager in the login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gdm/simple-greeter/banner_message_text \
      "Text of the warning banner here"

When entering a warning banner that spans several lines, remember to begin and end the string with `"`. This command writes directly either to the `/etc/gconf/gconf.xml.mandatory/%gconf-tree.xml` if it exists or to the file `/etc/gconf/gconf.xml.mandatory/apps/gdm/simple-greeter/%gconf.xml`. Either of these files can later be edited directly if necessary.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(c)

Set GUI Warning Banner Text

To set the text shown by the GNOME Display Manager in the login screen, run the following command:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gdm/simple-greeter/banner_message_text \
      "Text of the warning banner here"

When entering a warning banner that spans several lines, remember to begin and end the string with `"`. This command writes directly either to the `/etc/gconf/gconf.xml.mandatory/%gconf-tree.xml` if it exists or to the file `/etc/gconf/gconf.xml.mandatory/apps/gdm/simple-greeter/%gconf.xml`. Either of these files can later be edited directly if necessary.

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(a)

Modify the System Login Banner

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:
`Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.
This is a DoD interest computer system. All DoD interest computer systems and related equipment are intended for the communication, transmission, processing, and storage of official U.S. Government or other authorized information only. All DoD interest computer systems are subject to monitoring at all times to ensure proper functioning of equipment and systems including security devices and systems, to prevent unauthorized use and violations of statutes and security regulations, to deter criminal activity, and for other similar purposes. Any user of a DoD interest computer system should be aware that any information placed in the system is subject to monitoring and is not subject to any expectation of privacy.
If monitoring of this or any other DoD interest computer system reveals possible evidence of violation of criminal statutes, this evidence and any other related information, including identification information about the user, may be provided to law enforcement officials. If monitoring of this or any other DoD interest computer systems reveals violations of security regulations or unauthorized use, employees who violate security regulations or make unauthorized use of DoD interest computer systems are subject to appropriate disciplinary action.
Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.`
OR:
`I've read & consent to terms in IS user agreem't.`

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(b)

Modify the System Login Banner

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:
`Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.
This is a DoD interest computer system. All DoD interest computer systems and related equipment are intended for the communication, transmission, processing, and storage of official U.S. Government or other authorized information only. All DoD interest computer systems are subject to monitoring at all times to ensure proper functioning of equipment and systems including security devices and systems, to prevent unauthorized use and violations of statutes and security regulations, to deter criminal activity, and for other similar purposes. Any user of a DoD interest computer system should be aware that any information placed in the system is subject to monitoring and is not subject to any expectation of privacy.
If monitoring of this or any other DoD interest computer system reveals possible evidence of violation of criminal statutes, this evidence and any other related information, including identification information about the user, may be provided to law enforcement officials. If monitoring of this or any other DoD interest computer systems reveals violations of security regulations or unauthorized use, employees who violate security regulations or make unauthorized use of DoD interest computer systems are subject to appropriate disciplinary action.
Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.`
OR:
`I've read & consent to terms in IS user agreem't.`

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

AC-8(c)

Modify the System Login Banner

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:
`Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.
This is a DoD interest computer system. All DoD interest computer systems and related equipment are intended for the communication, transmission, processing, and storage of official U.S. Government or other authorized information only. All DoD interest computer systems are subject to monitoring at all times to ensure proper functioning of equipment and systems including security devices and systems, to prevent unauthorized use and violations of statutes and security regulations, to deter criminal activity, and for other similar purposes. Any user of a DoD interest computer system should be aware that any information placed in the system is subject to monitoring and is not subject to any expectation of privacy.
If monitoring of this or any other DoD interest computer system reveals possible evidence of violation of criminal statutes, this evidence and any other related information, including identification information about the user, may be provided to law enforcement officials. If monitoring of this or any other DoD interest computer systems reveals violations of security regulations or unauthorized use, employees who violate security regulations or make unauthorized use of DoD interest computer systems are subject to appropriate disciplinary action.
Use of this or any other DoD interest computer system constitutes consent to monitoring at all times.`
OR:
`I've read & consent to terms in IS user agreem't.`

An appropriate warning message reinforces policy awareness during the login process and facilitates possible legal action against attackers.

IA-5(b)

Set Password Hashing Algorithm in /etc/login.defs

In `/etc/login.defs`, add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm:

    ENCRYPT_METHOD SHA512

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(c)

Set Password Hashing Algorithm in /etc/login.defs

In `/etc/login.defs`, add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm:

    ENCRYPT_METHOD SHA512

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(1)(c)

Set Password Hashing Algorithm in /etc/login.defs

In `/etc/login.defs`, add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm:

    ENCRYPT_METHOD SHA512

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-7

Set Password Hashing Algorithm in /etc/login.defs

In `/etc/login.defs`, add or correct the following line to ensure the system will use SHA-512 as the hashing algorithm:

    ENCRYPT_METHOD SHA512

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(b)

Set Password Hashing Algorithm in /etc/pam.d/system-auth

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.

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(c)

Set Password Hashing Algorithm in /etc/pam.d/system-auth

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.

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(1)(c)

Set Password Hashing Algorithm in /etc/pam.d/system-auth

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.

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-7

Set Password Hashing Algorithm in /etc/pam.d/system-auth

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.

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(b)

Set Password Hashing Algorithm in /etc/libuser.conf

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

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(c)

Set Password Hashing Algorithm in /etc/libuser.conf

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

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-5(1)(c)

Set Password Hashing Algorithm in /etc/libuser.conf

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

Using a stronger hashing algorithm makes password cracking attacks more difficult.

IA-7

Set Password Hashing Algorithm in /etc/libuser.conf

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

Using a stronger hashing algorithm makes password cracking attacks more difficult.

AC-7(b)

Set Lockout Time For Failed Password Attempts

To configure the system to lock out accounts after a number of incorrect login attempts and require an administrator to unlock the account using `pam_faillock.so`, modify the content of both `/etc/pam.d/system-auth` and `/etc/pam.d/password-auth` as follows:

- Add the following line immediately `before` the `pam_unix.so` statement in the `AUTH` section:

      auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=

- Add the following line immediately `after` the `pam_unix.so` statement in the `AUTH` section:

      auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=

- Add the following line immediately `before` the `pam_unix.so` statement in the `ACCOUNT` section:

      account required pam_faillock.so

Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks. Ensuring that an administrator is involved in unlocking locked accounts draws appropriate attention to such situations.

IA-5(f)

Limit Password Reuse

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. In the file `/etc/pam.d/system-auth`, append `remember=` to the line which refers to the `pam_unix.so` or `pam_pwhistory.so`module, as shown below:

- for the `pam_unix.so` case:

      password sufficient pam_unix.so existing_options remember=

- for the `pam_pwhistory.so` case:

      password requisite pam_pwhistory.so existing_options remember=

The DoD STIG requirement is 5 passwords.

Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.

IA-5(1)(e)

Limit Password Reuse

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. In the file `/etc/pam.d/system-auth`, append `remember=` to the line which refers to the `pam_unix.so` or `pam_pwhistory.so`module, as shown below:

- for the `pam_unix.so` case:

      password sufficient pam_unix.so existing_options remember=

- for the `pam_pwhistory.so` case:

      password requisite pam_pwhistory.so existing_options remember=

The DoD STIG requirement is 5 passwords.

Preventing re-use of previous passwords helps ensure that a compromised password is not re-used by a user.

AC-7(a)

Set Interval For Counting Failed Password Attempts

Utilizing `pam_faillock.so`, the `fail_interval` directive configures the system to lock out accounts after a number of incorrect login attempts. Modify the content of both `/etc/pam.d/system-auth` and `/etc/pam.d/password-auth` as follows:

- Add the following line immediately `before` the `pam_unix.so` statement in the `AUTH` section:

      auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=

- Add the following line immediately `after` the `pam_unix.so` statement in the `AUTH` section:

      auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=

- Add the following line immediately `before` the `pam_unix.so` statement in the `ACCOUNT` section:

      account required pam_faillock.so

Locking out user accounts after a number of incorrect attempts within a specific period of time prevents direct password guessing attacks.

AC-7(a)

Set Deny For Failed Password Attempts

To configure the system to lock out accounts after a number of incorrect login attempts using `pam_faillock.so`, modify the content of both `/etc/pam.d/system-auth` and `/etc/pam.d/password-auth` as follows:

- Add the following line immediately `before` the `pam_unix.so` statement in the `AUTH` section:

      auth required pam_faillock.so preauth silent deny= unlock_time= fail_interval=

- Add the following line immediately `after` the `pam_unix.so` statement in the `AUTH` section:

      auth [default=die] pam_faillock.so authfail deny= unlock_time= fail_interval=

- Add the following line immediately `before` the `pam_unix.so` statement in the `ACCOUNT` section:

      account required pam_faillock.so

Locking out user accounts after a number of incorrect attempts prevents direct password guessing attacks.

IA-5(1)(a)

Set Password Minimum Length

The pam_cracklib module's `minlen` parameter controls requirements for minimum characters required in a password. Add `minlen=` after pam_pwquality to set minimum password length requirements.

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.

IA-5(c)

Set Password to Maximum of Three Consecutive Repeating Characters

The pam_cracklib 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. Add `maxrepeat=` after pam_cracklib.so to prevent a run of ( + 1) or more identical characters:

    password required pam_cracklib.so maxrepeat=

Passwords with excessive repeating characters may be more vulnerable to password-guessing attacks.

IA-5(b)

Set Password Strength Minimum Digit Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each digit. Add `dcredit=-1` after pam_cracklib.so to require use of a digit in passwords.

Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(c)

Set Password Strength Minimum Digit Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each digit. Add `dcredit=-1` after pam_cracklib.so to require use of a digit in passwords.

Requiring digits makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(b)

Set Password Strength Minimum Different Characters

The pam_cracklib module's `difok` parameter controls requirements for usage of different characters during a password change. Add `difok=` after pam_cracklib.so to require differing characters when changing passwords. The DoD requirement is `4`.

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.

IA-5(c)

Set Password Strength Minimum Different Characters

The pam_cracklib module's `difok` parameter controls requirements for usage of different characters during a password change. Add `difok=` after pam_cracklib.so to require differing characters when changing passwords. The DoD requirement is `4`.

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.

IA-5(1)(b)

Set Password Strength Minimum Different Characters

The pam_cracklib module's `difok` parameter controls requirements for usage of different characters during a password change. Add `difok=` after pam_cracklib.so to require differing characters when changing passwords. The DoD requirement is `4`.

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.

IA-5(b)

Set Password Strength Minimum Special Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each special character. Add `ocredit=` after pam_cracklib.so to require use of a special character in passwords.

Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(c)

Set Password Strength Minimum Special Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each special character. Add `ocredit=` after pam_cracklib.so to require use of a special character in passwords.

Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(1)(a)

Set Password Strength Minimum Special Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each special character. Add `ocredit=` after pam_cracklib.so to require use of a special character in passwords.

Requiring a minimum number of special characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(b)

Set Password Strength Minimum Lowercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each lowercase character. Add `lcredit=-1` after pam_cracklib.so to require use of a lowercase character in passwords.

Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(c)

Set Password Strength Minimum Lowercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each lowercase character. Add `lcredit=-1` after pam_cracklib.so to require use of a lowercase character in passwords.

Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(1)(a)

Set Password Strength Minimum Lowercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each lowercase character. Add `lcredit=-1` after pam_cracklib.so to require use of a lowercase character in passwords.

Requiring a minimum number of lowercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(b)

Set Password Strength Minimum Uppercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each uppercase character. Add `ucredit=-1` after pam_cracklib.so to require use of an upper case character in passwords.

Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(c)

Set Password Strength Minimum Uppercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each uppercase character. Add `ucredit=-1` after pam_cracklib.so to require use of an upper case character in passwords.

Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(1)(a)

Set Password Strength Minimum Uppercase Characters

The pam_cracklib 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_cracklib will grant +1 additional length credit for each uppercase character. Add `ucredit=-1` after pam_cracklib.so to require use of an upper case character in passwords.

Requiring a minimum number of uppercase characters makes password guessing attacks more difficult by ensuring a larger search space.

IA-5(c)

Set Password Retry Prompts Permitted Per-Session

To configure the number of retry prompts that are permitted per-session:
Edit the `pam_cracklib.so` statement in `/etc/pam.d/system-auth` to show `retry=`, or a lower value if site policy is more restrictive.
The DoD requirement is a maximum of 3 prompts per session.

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.

AC-6

Verify Permissions on shadow File

To properly set the permissions of `/etc/shadow`, run the command:

    $ sudo chmod 0000 /etc/shadow

The `/etc/shadow` file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

AC-6

Verify Group Who Owns shadow File

To properly set the group owner of `/etc/shadow`, run the command:

    $ sudo chgrp root /etc/shadow

The `/etc/shadow` file stores password hashes. Protection of this file is critical for system security.

AC-6

Verify User Who Owns group File

To properly set the owner of `/etc/group`, run the command:

    $ sudo chown root /etc/group

The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

AC-6

Verify Permissions on group File

To properly set the permissions of `/etc/group`, run the command:

    $ sudo chmod 644 /etc/group

The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

AC-6

Verify User Who Owns passwd File

To properly set the owner of `/etc/passwd`, run the command:

    $ sudo chown root /etc/passwd

The `/etc/passwd` file contains information about the users that are configured on the system. Protection of this file is critical for system security.

AC-6

Verify Group Who Owns gshadow File

To properly set the group owner of `/etc/gshadow`, run the command:

    $ sudo chgrp root /etc/gshadow

The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.

AC-6

Verify Group Who Owns passwd File

To properly set the group owner of `/etc/passwd`, run the command:

    $ sudo chgrp root /etc/passwd

The `/etc/passwd` file contains information about the users that are configured on the system. Protection of this file is critical for system security.

AC-6

Verify User Who Owns gshadow File

To properly set the owner of `/etc/gshadow`, run the command:

    $ sudo chown root /etc/gshadow

The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.

AC-6

Verify Group Who Owns group File

To properly set the group owner of `/etc/group`, run the command:

    $ sudo chgrp root /etc/group

The `/etc/group` file contains information regarding groups that are configured on the system. Protection of this file is important for system security.

AC-6

Verify Permissions on gshadow File

To properly set the permissions of `/etc/gshadow`, run the command:

    $ sudo chmod 0000 /etc/gshadow

The `/etc/gshadow` file contains group password hashes. Protection of this file is critical for system security.

AC-6

Verify User Who Owns shadow File

To properly set the owner of `/etc/shadow`, run the command:

    $ sudo chown root /etc/shadow

The `/etc/shadow` file contains the list of local system accounts and stores password hashes. Protection of this file is critical for system security. Failure to give ownership of this file to root provides the designated owner with access to sensitive information which could weaken the system security posture.

AC-6

Verify Permissions on passwd File

To properly set the permissions of `/etc/passwd`, run the command:

    $ sudo chmod 0644 /etc/passwd

If the `/etc/passwd` file is writable by a group-owner or the world the risk of its compromise is increased. The file contains the list of accounts on the system and associated information, and protection of this file is critical for system security.

AC-6

Verify that Shared Library Files Have Root Ownership

System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:

    /lib
    /lib64
    /usr/lib
    /usr/lib64

Kernel modules, which can be added to the kernel during runtime, are also stored in `/lib/modules`. All files in these directories should be owned by the `root` user. If the directory, or any file in these directories, is found to be owned by a user other than root correct its ownership with the following command:

    $ sudo chown root FILE

Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Proper ownership is necessary to protect the integrity of the system.

AC-6

Verify that System Executables Have Restrictive Permissions

System executables are stored in the following directories by default:

    /bin
    /sbin
    /usr/bin
    /usr/libexec
    /usr/local/bin
    /usr/local/sbin
    /usr/sbin

All files in these directories should not be group-writable or world-writable. If any file FILE in these directories is found to be group-writable or world-writable, correct its permission with the following command:

    $ sudo chmod go-w FILE

System binaries are executed by privileged users, as well as system services, and restrictive permissions are necessary to ensure execution of these programs cannot be co-opted.

AC-6

Verify that System Executables Have Root Ownership

System executables are stored in the following directories by default:

    /bin
    /sbin
    /usr/bin
    /usr/libexec
    /usr/local/bin
    /usr/local/sbin
    /usr/sbin

All files in these directories should be owned by the `root` user. If any file FILE in these directories is found to be owned by a user other than root, correct its ownership with the following command:

    $ sudo chown root FILE

System binaries are executed by privileged users as well as system services, and restrictive permissions are necessary to ensure that their execution of these programs cannot be co-opted.

AC-6

Verify that Shared Library Files Have Restrictive Permissions

System-wide shared library files, which are linked to executables during process load time or run time, are stored in the following directories by default:

    /lib
    /lib64
    /usr/lib
    /usr/lib64

Kernel modules, which can be added to the kernel during runtime, are stored in `/lib/modules`. All files in these directories should not be group-writable or world-writable. If any file in these directories is found to be group-writable or world-writable, correct its permission with the following command:

    $ sudo chmod go-w FILE

Files from shared library directories are loaded into the address space of processes (including privileged ones) or of the kernel itself at runtime. Restrictive permissions are necessary to protect the integrity of the system.

AC-6(1)

Ensure All SGID Executables Are Authorized

The SGID (set group id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorized SGID files is determine if any were not installed as part of an RPM package, which is cryptographically verified. Investigate the origin of any unpackaged SGID files.

Executable files with the SGID permission run with the privileges of the owner of the file. SGID files of uncertain provenance could allow for unprivileged users to elevate privileges. The presence of these files should be strictly controlled on the system.

AC-6

Ensure All Files Are Owned by a Group

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.

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.

AC-6

Ensure All World-Writable Directories Are Owned by a System Account

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 group.

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.

AC-6

Ensure All Files Are Owned by a User

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.

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.

AC-6

Ensure No World-Writable Files Exist

It is generally a good idea to remove global (other) write access to a file when it is discovered. However, check with documentation for specific applications before making changes. Also, monitor for recurring world-writable files, as these may be symptoms of a misconfigured application or user account. Finally, this applies to real files and not virtual files that are a part of pseudo file systems such as `sysfs` or `procfs`.

Data in world-writable files can be modified by any user on the system. In almost all circumstances, files can be configured using a combination of user and group permissions to support whatever legitimate access is needed without the risk caused by world-writable files.

AC-6

Verify that All World-Writable Directories Have Sticky Bits Set

When the so-called 'sticky bit' is set on a directory, only the owner of a given file may remove that file from the directory. Without the sticky bit, any user with write access to a directory may remove any file in the directory. Setting the sticky bit prevents users from removing each other's files. In cases where there is no reason for a directory to be world-writable, a better solution is to remove that permission rather than to set the sticky bit. However, if a directory is used by a particular application, consult that application's documentation instead of blindly changing modes.
To set the sticky bit on a world-writable directory DIR, run the following command:

    $ sudo chmod +t DIR

Failing to set the sticky bit on public directories allows unauthorized users to delete files in the directory structure.
The only authorized public directories are those temporary directories supplied with the system, or those designed to be temporary file repositories. The setting is normally reserved for directories used by the system, by users for temporary file storage (such as `/tmp`), and for directories requiring global read/write access.

AC-6(1)

Ensure All SUID Executables Are Authorized

The SUID (set user id) bit should be set only on files that were installed via authorized means. A straightforward means of identifying unauthorized SGID files is determine if any were not installed as part of an RPM package, which is cryptographically verified. Investigate the origin of any unpackaged SUID files.

Executable files with the SUID permission run with the privileges of the owner of the file. SUID files of uncertain provenance could allow for unprivileged users to elevate privileges. The presence of these files should be strictly controlled on the system.

AC-19(a)

Disable Modprobe Loading of USB Storage Driver

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 a file in the directory `/etc/modprobe.d`:

    install usb-storage /bin/true

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.

USB storage devices such as thumb drives can be used to introduce malicious software.

AC-19(d)

Disable Modprobe Loading of USB Storage Driver

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 a file in the directory `/etc/modprobe.d`:

    install usb-storage /bin/true

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.

USB storage devices such as thumb drives can be used to introduce malicious software.

AC-19(e)

Disable Modprobe Loading of USB Storage Driver

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 a file in the directory `/etc/modprobe.d`:

    install usb-storage /bin/true

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.

USB storage devices such as thumb drives can be used to introduce malicious software.

AC-19(a)

Disable Kernel Support for USB via Bootloader Configuration

All USB support can be disabled by adding the `nousb` argument to the kernel's boot loader configuration. To do so, append "nousb" to the kernel line in `/etc/grub.conf` as shown:

    kernel /vmlinuz-VERSION ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet nousb

WARNING: Disabling all kernel support for USB will cause problems for systems with USB-based keyboards, mice, or printers. This configuration is infeasible for systems which require USB devices, which is common.

Disabling the USB subsystem within the Linux kernel at system boot will protect against potentially malicious USB devices, although it is only practical in specialized systems.

AC-19(d)

Disable Kernel Support for USB via Bootloader Configuration

All USB support can be disabled by adding the `nousb` argument to the kernel's boot loader configuration. To do so, append "nousb" to the kernel line in `/etc/grub.conf` as shown:

    kernel /vmlinuz-VERSION ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet nousb

WARNING: Disabling all kernel support for USB will cause problems for systems with USB-based keyboards, mice, or printers. This configuration is infeasible for systems which require USB devices, which is common.

Disabling the USB subsystem within the Linux kernel at system boot will protect against potentially malicious USB devices, although it is only practical in specialized systems.

AC-19(e)

Disable Kernel Support for USB via Bootloader Configuration

All USB support can be disabled by adding the `nousb` argument to the kernel's boot loader configuration. To do so, append "nousb" to the kernel line in `/etc/grub.conf` as shown:

    kernel /vmlinuz-VERSION ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet nousb

WARNING: Disabling all kernel support for USB will cause problems for systems with USB-based keyboards, mice, or printers. This configuration is infeasible for systems which require USB devices, which is common.

Disabling the USB subsystem within the Linux kernel at system boot will protect against potentially malicious USB devices, although it is only practical in specialized systems.

AC-19(a) | Disable Booting from USB Devices in Boot Firmware | Configure the system boot firmware (historically called BIOS on PC systems) to disallow booting from USB drives. | Booting a system from a USB device would allow an attacker to circumvent any security measures provided by the operating system. Attackers could mount partitions and modify the configuration of the OS. |
AC-19(d) | Disable Booting from USB Devices in Boot Firmware | Configure the system boot firmware (historically called BIOS on PC systems) to disallow booting from USB drives. | Booting a system from a USB device would allow an attacker to circumvent any security measures provided by the operating system. Attackers could mount partitions and modify the configuration of the OS. |
AC-19(e) | Disable Booting from USB Devices in Boot Firmware | Configure the system boot firmware (historically called BIOS on PC systems) to disallow booting from USB drives. | Booting a system from a USB device would allow an attacker to circumvent any security measures provided by the operating system. Attackers could mount partitions and modify the configuration of the OS. |

AC-19(a)

Disable the Automounter

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 chkconfig autofs off

Disabling the automounter permits the administrator to statically control filesystem mounting through `/etc/fstab`.

AC-19(d)

Disable the Automounter

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 chkconfig autofs off

Disabling the automounter permits the administrator to statically control filesystem mounting through `/etc/fstab`.

AC-19(e)

Disable the Automounter

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 chkconfig autofs off

Disabling the automounter permits the administrator to statically control filesystem mounting through `/etc/fstab`.

CM-7

Disable Mounting of udf

To configure the system to prevent the `udf` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install udf /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of squashfs

To configure the system to prevent the `squashfs` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install squashfs /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of hfsplus

To configure the system to prevent the `hfsplus` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install hfsplus /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of jffs2

To configure the system to prevent the `jffs2` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install jffs2 /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of hfs

To configure the system to prevent the `hfs` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install hfs /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of cramfs

To configure the system to prevent the `cramfs` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install cramfs /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Disable Mounting of freevxfs

To configure the system to prevent the `freevxfs` kernel module from being loaded, add the following line to a file in the directory `/etc/modprobe.d`:

    install freevxfs /bin/true

This effectively prevents usage of this uncommon filesystem.

Linux kernel modules which implement filesystems that are not needed by the local system should be disabled.

CM-7

Add noexec Option to /dev/shm

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`.

Allowing users to execute binaries from world-writable directories such as `/dev/shm` can expose the system to potential compromise.

MP-2

Add noexec Option to /dev/shm

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`.

Allowing users to execute binaries from world-writable directories such as `/dev/shm` can expose the system to potential compromise.

CM-7

Add nosuid Option to /dev/shm

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`.

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.

MP-2

Add nosuid Option to /dev/shm

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`.

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.

CM-7

Add nodev Option to /tmp

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`.

The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.

MP-2

Add nodev Option to /tmp

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`.

The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.

CM-7

Add noexec Option to /tmp

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`.

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.

MP-2

Add noexec Option to /tmp

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`.

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.

CM-7

Add nosuid Option to /tmp

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`.

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.

MP-2

Add nosuid Option to /tmp

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`.

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.

AC-19(a)

Add nosuid Option to Removable Media Partitions

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.

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.

AC-19(d)

Add nosuid Option to Removable Media Partitions

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.

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.

AC-19(e)

Add nosuid Option to Removable Media Partitions

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.

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.

CM-7

Add nosuid Option to Removable Media Partitions

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.

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.

MP-2

Add nosuid Option to Removable Media Partitions

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.

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.

CM-7

Add nodev Option to Non-Root Local Partitions

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 non-root local partitions.

The `nodev` mount option prevents files from being interpreted as character or block devices. The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails, for which it is not advised to set `nodev` on these filesystems.

AC-19(a)

Add nodev Option to Removable Media Partitions

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.

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.

AC-19(d)

Add nodev Option to Removable Media Partitions

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.

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.

AC-19(e)

Add nodev Option to Removable Media Partitions

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.

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.

CM-7

Add nodev Option to Removable Media Partitions

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.

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.

MP-2

Add nodev Option to Removable Media Partitions

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.

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.

AC-19(a)

Add noexec Option to Removable Media Partitions

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.

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

AC-19(d)

Add noexec Option to Removable Media Partitions

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.

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

AC-19(e)

Add noexec Option to Removable Media Partitions

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.

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

CM-7

Add noexec Option to Removable Media Partitions

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.

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

MP-2

Add noexec Option to Removable Media Partitions

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.

Allowing users to execute binaries from removable media such as USB keys exposes the system to potential compromise.

CM-7

Bind Mount /var/tmp To /tmp

The `/var/tmp` directory is a world-writable directory. Bind-mount it to `/tmp` in order to consolidate temporary storage into one location protected by the same techniques as `/tmp`. To do so, edit `/etc/fstab` and add the following line:

    /tmp     /var/tmp     none     rw,nodev,noexec,nosuid,bind     0 0

See the `mount(8)` man page for further explanation of bind mounting.

Having multiple locations for temporary storage is not required. Unless absolutely necessary to meet requirements, the storage location `/var/tmp` should be bind mounted to `/tmp` and thus share the same protections.

CM-7

Add nodev Option to /dev/shm

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`.

The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.

MP-2

Add nodev Option to /dev/shm

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`.

The only legitimate location for device files is the `/dev` directory located on the root partition. The only exception to this is chroot jails.

AC-6

Set Daemon Umask

The file `/etc/init.d/functions` includes initialization parameters for most or all daemons started at boot time. The default umask of 022 prevents creation of group- or world-writable files. To set the default umask for daemons, edit the following line, inserting 022 or 027 for umask appropriately:

    umask

Setting the umask to too restrictive a setting can cause serious errors at runtime. Many daemons on the system already individually restrict themselves to a umask of 077 in their own init scripts.

The umask influences the permissions assigned to files created by a process at run time. An unnecessarily permissive umask could result in files being created with insecure permissions.

CM-6(b)

Install PAE Kernel on Supported 32-bit x86 Systems

Systems that are using the 64-bit x86 kernel package do not need to install the kernel-PAE package because the 64-bit x86 kernel already includes this support. However, if the system is 32-bit and also supports the PAE and NX features as determined in the previous section, the kernel-PAE package should be installed to enable XD or NX support:

    $ sudo yum install kernel-PAE

The installation process should also have configured the bootloader to load the new kernel at boot. Verify this at reboot and modify `/etc/grub.conf` if necessary.

On 32-bit systems that support the XD or NX bit, the vendor-supplied PAE kernel is required to enable either Execute Disable (XD) or No Execute (NX) support.

CM-6(b)

Enable NX or XD Support in the BIOS

Reboot the system and enter the BIOS or Setup configuration menu. Navigate the BIOS configuration menu and make sure that the option is enabled. The setting may be located under a Security section. Look for Execute Disable (XD) on Intel-based systems and No Execute (NX) on AMD-based systems.

Computers with the ability to prevent this type of code execution frequently put an option in the BIOS that will allow users to turn the feature on or off at will.

SI-11

Disable Core Dumps for SUID programs

To set the runtime status of the `fs.suid_dumpable` kernel parameter, run the following command:

    $ sudo sysctl -w fs.suid_dumpable=0

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    fs.suid_dumpable = 0

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.

SC-5

Disable Core Dumps for All Users

To disable core dumps for all users, add the following line to `/etc/security/limits.conf`:

    *     hard   core    0

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.

SC-39

Enable ExecShield

To set the runtime status of the `kernel.exec-shield` kernel parameter, run the following command:

    $ sudo sysctl -w kernel.exec-shield=1

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    kernel.exec-shield = 1

ExecShield uses the segmentation feature on all x86 systems to prevent execution in memory higher than a certain address. It writes an address as a limit in the code segment descriptor, to control where code can be executed, on a per-process basis. When the kernel places a process's memory regions such as the stack and heap higher than this address, the hardware prevents execution in that address range.

SC-30(2)

Enable Randomized Layout of Virtual Address Space

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

If this is not the system's default value, add the following line to `/etc/sysctl.conf`:

    kernel.randomize_va_space = 2

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.

AU-9

Configure auditd flush priority

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 =

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.

AU-12(1)

Configure auditd flush priority

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 =

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.

AU-1(b)

Configure auditd to use audispd's syslog plugin

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

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

AU-3(2)

Configure auditd to use audispd's syslog plugin

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

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

IR-5

Configure auditd to use audispd's syslog plugin

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

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

AU-1(b)

Configure auditd Disk Full Action when Disk Space Is Full

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:

    disk_full_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.

AU-4

Configure auditd Disk Full Action when Disk Space Is Full

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:

    disk_full_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.

AU-5(b)

Configure auditd Disk Full Action when Disk Space Is Full

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:

    disk_full_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.

IR-5

Configure auditd Disk Full Action when Disk Space Is Full

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:

    disk_full_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of a filled audit storage volume will minimize the possibility of losing audit records.

AU-1(b)

Configure auditd Max Log File Size

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 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.

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.

AU-11

Configure auditd Max Log File Size

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 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.

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.

IR-5

Configure auditd Max Log File Size

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 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.

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.

AU-1(b)

Configure auditd space_left on Low Disk Space

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 SIZE_in_MB appropriately:

    space_left = SIZE_in_MB

Set this value to the appropriate size in Megabytes cause the system to notify the user of an issue.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-4

Configure auditd space_left on Low Disk Space

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 SIZE_in_MB appropriately:

    space_left = SIZE_in_MB

Set this value to the appropriate size in Megabytes cause the system to notify the user of an issue.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-5(b)

Configure auditd space_left on Low Disk Space

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 SIZE_in_MB appropriately:

    space_left = SIZE_in_MB

Set this value to the appropriate size in Megabytes cause the system to notify the user of an issue.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

IR-5

Configure auditd space_left on Low Disk Space

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 SIZE_in_MB appropriately:

    space_left = SIZE_in_MB

Set this value to the appropriate size in Megabytes cause the system to notify the user of an issue.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-1(b)

Configure auditd mail_acct Action on Low Disk Space

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 =

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

AU-4

Configure auditd mail_acct Action on Low Disk Space

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 =

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

AU-5(a)

Configure auditd mail_acct Action on Low Disk Space

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 =

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

IR-5

Configure auditd mail_acct Action on Low Disk Space

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 =

Email sent to the root account is typically aliased to the administrators of the system, who can take appropriate action.

AU-1(b)

Configure auditd admin_space_left Action on Low Disk Space

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.

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.

AU-4

Configure auditd admin_space_left Action on Low Disk Space

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.

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.

AU-5(b)

Configure auditd admin_space_left Action on Low Disk Space

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.

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.

IR-5

Configure auditd admin_space_left Action on Low Disk Space

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.

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.

AU-1(b)

Configure auditd space_left Action on Low Disk Space

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:

- `ignore`
- `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`.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-4

Configure auditd space_left Action on Low Disk Space

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:

- `ignore`
- `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`.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-5(b)

Configure auditd space_left Action on Low Disk Space

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:

- `ignore`
- `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`.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

IR-5

Configure auditd space_left Action on Low Disk Space

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:

- `ignore`
- `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`.

Notifying administrators of an impending disk space problem may allow them to take corrective action prior to any disruption.

AU-1(b)

Configure auditd Disk Error Action on Disk Error

The `auditd` service can be configured to take an action when there is a disk error. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting ACTION appropriately:

    disk_error_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of disk errors will minimize the possibility of losing audit records.

AU-4

Configure auditd Disk Error Action on Disk Error

The `auditd` service can be configured to take an action when there is a disk error. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting ACTION appropriately:

    disk_error_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of disk errors will minimize the possibility of losing audit records.

AU-5(b)

Configure auditd Disk Error Action on Disk Error

The `auditd` service can be configured to take an action when there is a disk error. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting ACTION appropriately:

    disk_error_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of disk errors will minimize the possibility of losing audit records.

IR-5

Configure auditd Disk Error Action on Disk Error

The `auditd` service can be configured to take an action when there is a disk error. Edit the file `/etc/audit/auditd.conf`. Add or modify the following line, substituting ACTION appropriately:

    disk_error_action = ACTION

Set this value to `single` to cause the system to switch to single-user mode for corrective action. Acceptable values also include `syslog`, `exec`, `single`, 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.

Taking appropriate action in case of disk errors will minimize the possibility of losing audit records.

AU-1(b)

Configure auditd Number of Logs Retained

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 :

    num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

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.

AU-11

Configure auditd Number of Logs Retained

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 :

    num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

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.

IR-5

Configure auditd Number of Logs Retained

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 :

    num_logs = NUMLOGS

Set the value to 5 for general-purpose systems. Note that values less than 2 result in no log rotation.

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.

AU-1(b)

Configure auditd max_log_file_action Upon Reaching Maximum Log Size

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.

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.

AU-4

Configure auditd max_log_file_action Upon Reaching Maximum Log Size

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.

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.

AU-11

Configure auditd max_log_file_action Upon Reaching Maximum Log Size

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.

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.

IR-5

Configure auditd max_log_file_action Upon Reaching Maximum Log Size

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.

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - setxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S setxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - chown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - lsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - lchown

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lchown -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - chmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S chmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S chmod  -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - removexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S removexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fchmod

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmod -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fchownat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchownat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - lremovexattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S lremovexattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fsetxattr

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fsetxattr -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-1(b)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(a)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(c)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-2(d)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(a)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AU-12(c)

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

IR-5

Record Events that Modify the System's Discretionary Access Controls - fchmodat

At a minimum the audit system should collect file permission changes for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S fchmodat -F auid>=500 -F auid!=4294967295 -k perm_mod

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.

AC-3(10)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-1(b)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-2(a)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-2(c)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-2(d)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-12(a)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AU-12(c)

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

IR-5

Record Attempts to Alter Time Through stime

Add the following line to `/etc/audit/audit.rules` for both 32-bit and 64-bit systems:

    # audit_time_rules
    -a always,exit -F arch=b32 -S stime -k 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 syscalls:

    -a always,exit -F arch=b64 -S adjtimex -S settimeofday -k audit_time_rules

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.

AC-3(10)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-1(b)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(a)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(c)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(d)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-12(a)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AU-12(c)

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

IR-5

Record attempts to alter time through settimeofday

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S settimeofday -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S settimeofday -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. 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 -S settimeofday -k audit_time_rules

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.

AC-3(10)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-1(b)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-2(a)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-2(c)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-2(d)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-12(a)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AU-12(c)

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

IR-5

Record Attempts to Alter the localtime File

Add the following to `/etc/audit/audit.rules`:

    -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.

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.

AC-3(10)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-1(b)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-2(a)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-2(c)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-2(d)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-12(a)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AU-12(c)

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

IR-5

Record Attempts to Alter Time Through clock_settime

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -a always,exit -F arch=b32 -S clock_settime -F a0=0x0 -F key=time-change

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # time-change
    -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 -S settimeofday -k audit_time_rules

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.

AC-3(10)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-1(b)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(a)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(c)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-2(d)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-12(a)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AU-12(c)

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

IR-5

Record attempts to alter time through adjtimex

On a 32-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b32 -S adjtimex -k audit_time_rules

On a 64-bit system, add the following to `/etc/audit/audit.rules`:

    # audit_time_rules
    -a always,exit -F arch=b64 -S adjtimex -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. 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 -S settimeofday -k audit_time_rules

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.

AC-3(10)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-1(b)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-2(a)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-2(c)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-2(d)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-12(a)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AU-12(c)

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

IR-5

Ensure auditd Collects Information on Kernel Module Loading and Unloading

Add the following to `/etc/audit/audit.rules` in order to capture kernel module loading and unloading events, setting ARCH to either b32 or b64 as appropriate for your system:

    -w /sbin/insmod -p x -k modules
    -w /sbin/rmmod -p x -k modules
    -w /sbin/modprobe -p x -k modules
    -a always,exit -F arch=ARCH -S init_module -S delete_module -k modules

The addition/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.

AC-3(10))

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-1(b)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-2(a)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-2(c)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-2(d)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AC-6(9)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-12(a)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AU-12(c)

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

IR-5

Ensure auditd Collects Information on the Use of Privileged Commands

At a minimum the audit system should collect the execution of privileged commands for all users and root. To find the relevant setuid / setgid programs, run the following command for each local partition PART:

    $ sudo find PART -xdev -type f -perm -4000 -o -type f -perm -2000 2>/dev/null

Then, for each setuid / setgid program on the system, add a line of the following form to `/etc/audit/audit.rules`, where SETUID_PROG_PATH is the full path to each setuid / setgid program in the list:

    -a always,exit -F path=SETUID_PROG_PATH -F perm=x -F auid>=500 -F auid!=4294967295 -k privileged

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.

AC-3(10)

Record Attempts to Alter Login and Logout Events

The audit system already collects login info for all users and root. To watch for attempted manual edits of files involved in storing login events, add the following to `/etc/audit/audit.rules`:

    -w /var/log/tallylog -p wa -k logins
    -w /var/run/faillock/ -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-1(b)

Record Attempts to Alter Login and Logout Events

The audit system already collects login info for all users and root. To watch for attempted manual edits of files involved in storing login events, add the following to `/etc/audit/audit.rules`:

    -w /var/log/tallylog -p wa -k logins
    -w /var/run/faillock/ -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-12(a)

Record Attempts to Alter Login and Logout Events

The audit system already collects login info for all users and root. To watch for attempted manual edits of files involved in storing login events, add the following to `/etc/audit/audit.rules`:

    -w /var/log/tallylog -p wa -k logins
    -w /var/run/faillock/ -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-12(c)

Record Attempts to Alter Login and Logout Events

The audit system already collects login info for all users and root. To watch for attempted manual edits of files involved in storing login events, add the following to `/etc/audit/audit.rules`:

    -w /var/log/tallylog -p wa -k logins
    -w /var/run/faillock/ -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

IR-5

Record Attempts to Alter Login and Logout Events

The audit system already collects login info for all users and root. To watch for attempted manual edits of files involved in storing login events, add the following to `/etc/audit/audit.rules`:

    -w /var/log/tallylog -p wa -k logins
    -w /var/run/faillock/ -p wa -k logins
    -w /var/log/lastlog -p wa -k logins

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AC-2(7)(b)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AC-3(10)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-1(b)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-2(a)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-2(c)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-2(d)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-12(a)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AU-12(c)

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

IR-5

Ensure auditd Collects System Administrator Actions

At a minimum the audit system should collect administrator actions for all users and root. Add the following to `/etc/audit/audit.rules`:

    -w /etc/sudoers -p wa -k actions

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.

AC-3(10)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-1(b)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-2(a)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-2(c)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-2(d)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-12(a)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AU-12(c)

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

IR-5

Record Events that Modify the System's Network Environment

Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    # audit_rules_networkconfig_modification
    -a always,exit -F arch=ARCH -S sethostname -S setdomainname -k 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

The network environment should not be modified by anything other than administrator action. Any change to network parameters should be audited.

AC-2(4)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AC-3(10)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-1(b)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-2(a)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-2(c)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-2(d)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-12(a)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AU-12(c)

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

IR-5

Record Events that Modify User/Group Information

Add the following to `/etc/audit/audit.rules`, in order to capture events that modify account changes:

    # audit_rules_usergroup_modification
    -w /etc/group -p wa -k audit_rules_usergroup_modification
    -w /etc/passwd -p wa -k audit_rules_usergroup_modification
    -w /etc/gshadow -p wa -k audit_rules_usergroup_modification
    -w /etc/shadow -p wa -k audit_rules_usergroup_modification
    -w /etc/security/opasswd -p wa -k audit_rules_usergroup_modification

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.

AC-6

System Audit Logs Must Have Mode 0750 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0750 /var/log/audit

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0700 /var/log/audit

If users can write to audit logs, audit trails can be modified or destroyed.

AU-1(b)

System Audit Logs Must Have Mode 0750 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0750 /var/log/audit

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0700 /var/log/audit

If users can write to audit logs, audit trails can be modified or destroyed.

AU-9

System Audit Logs Must Have Mode 0750 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0750 /var/log/audit

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0700 /var/log/audit

If users can write to audit logs, audit trails can be modified or destroyed.

IR-5

System Audit Logs Must Have Mode 0750 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0750 /var/log/audit

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0700 /var/log/audit

If users can write to audit logs, audit trails can be modified or destroyed.

AC-3(10)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-1(b)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-2(a)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-2(c)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-2(d)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-12(a)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AU-12(c)

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

IR-5

Record Attempts to Alter Process and Session Initiation Information

The audit system already collects process information for all users and root. To watch for attempted manual edits of files involved in storing such process information, add the following to `/etc/audit/audit.rules`:

    -w /var/run/utmp -p wa -k session
    -w /var/log/btmp -p wa -k session
    -w /var/log/wtmp -p wa -k session

Manual editing of these files may indicate nefarious activity, such as an attacker attempting to remove evidence of an intrusion.

AC-3(10)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-1(b)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-2(a)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-2(c)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-2(d)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-12(a)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AU-12(c)

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

IR-5

Ensure auditd Collects Unauthorized Access Attempts to Files (unsuccessful)

At a minimum the audit system should collect unauthorized file accesses for all users and root. Add the following to `/etc/audit/audit.rules`:

    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b32 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

If the system is 64 bit then also add the following:

    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EACCES -F auid>=500 -F auid!=4294967295 -k access
    -a always,exit -F arch=b64 -S creat -S open -S openat -S open_by_handle_at -S truncate -S ftruncate -F exit=-EPERM -F auid>=500 -F auid!=4294967295 -k access

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.

AC-3(10)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-1(b)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-2(a)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-2(c)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-2(d)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-12(a)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AU-12(c)

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

IR-5

Ensure auditd Collects File Deletion Events by User

At a minimum the audit system should collect file deletion events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S rmdir -S unlink -S unlinkat -S rename -S renameat -F auid>=500 -F auid!=4294967295 -k delete

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.

AC-3(10)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-1(b)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-2(a)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-2(c)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-2(d)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-12(a)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AU-12(c)

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

IR-5

Ensure auditd Collects Information on Exporting to Media (successful)

At a minimum the audit system should collect media exportation events for all users and root. Add the following to `/etc/audit/audit.rules`, setting ARCH to either b32 or b64 as appropriate for your system:

    -a always,exit -F arch=ARCH -S mount -F auid>=500 -F auid!=4294967295 -k export

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.

AC-6

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

AU-1(b)

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

AU-2(a)

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

AU-2(c)

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

AU-2(d)

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

IR-5

Make the auditd Configuration Immutable

Add the following to `/etc/audit/audit.rules` in order to make the configuration immutable:

    -e 2

With this setting, a reboot will be required to change any audit rules.

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

AC-6

System Audit Logs Must Be Owned By Root

To properly set the owner of `/var/log`, run the command:

    $ sudo chown root /var/log

Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.

AU-1(b)

System Audit Logs Must Be Owned By Root

To properly set the owner of `/var/log`, run the command:

    $ sudo chown root /var/log

Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.

AU-9

System Audit Logs Must Be Owned By Root

To properly set the owner of `/var/log`, run the command:

    $ sudo chown root /var/log

Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.

IR-5

System Audit Logs Must Be Owned By Root

To properly set the owner of `/var/log`, run the command:

    $ sudo chown root /var/log

Failure to give ownership of the audit log files to root allows the designated owner, and unauthorized users, potential access to sensitive information.

AC-6

System Audit Logs Must Have Mode 0640 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0640 audit_file

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0600 audit_file

If users can write to audit logs, audit trails can be modified or destroyed.

AU-1(b)

System Audit Logs Must Have Mode 0640 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0640 audit_file

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0600 audit_file

If users can write to audit logs, audit trails can be modified or destroyed.

AU-9

System Audit Logs Must Have Mode 0640 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0640 audit_file

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0600 audit_file

If users can write to audit logs, audit trails can be modified or destroyed.

IR-5

System Audit Logs Must Have Mode 0640 or Less Permissive

If `log_group` in `/etc/audit/auditd.conf` is set to a group other than the `root` group account, change the mode of the audit log files with the following command:

    $ sudo chmod 0640 audit_file

Otherwise, change the mode of the audit log files with the following command:

    $ sudo chmod 0600 audit_file

If users can write to audit logs, audit trails can be modified or destroyed.

AC-3(10)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-1(b)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-2(a)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-2(c)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-2(d)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-12(a)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AU-12(c)

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

IR-5

Record Events that Modify the System's Mandatory Access Controls

Add the following to `/etc/audit/audit.rules`:

    -w /etc/selinux/ -p wa -k MAC-policy

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.

AC-17(1)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-14(1)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-1(b)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-2(a)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-2(c)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-2(d)

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AU-10

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

IR-5

Enable Auditing for Processes Which Start Prior to the Audit Daemon

To ensure all processes can be audited, even those which start prior to the audit daemon, add the argument `audit=1` to the kernel line in `/etc/grub.conf`, in the manner below:

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet audit=1

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.

AC-17(1)

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

AU-1(b)

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

AU-10

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

AU-12(a)

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

AU-12(c)

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

IR-5

Enable auditd Service

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 chkconfig --level 2345 auditd on

Ensuring the `auditd` service is active ensures audit records generated by the kernel can be written to disk, or that appropriate actions will be taken if other obstacles exist.

IA-11

Ensure Users Re-Authenticate for Privilege Escalation - sudo

The sudo `NOPASSWD` and `!authenticate` option, when specified, allows a user to execute commands using sudo without having to authenticate. This should be disabled by making sure that `NOPASSWD` and/or `!authenticate` do not exist in `/etc/sudoers` configuration file or any sudo configuration snippets in `/etc/sudoers.d/`.

Without re-authentication, users may access resources or perform tasks for which they do not have authorization.
When operating systems provide the capability to escalate a functional capability, it is critical that the user re-authenticate.

AC-17(2)

Install the dracut-fips Package

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

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.

AC-17(2)

Enable FIPS Mode in GRUB

To ensure FIPS mode is enabled, rebuild `initramfs` by running the following command:

    dracut -f

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

    kernel /vmlinuz-version ro vga=ext root=/dev/VolGroup00/LogVol00 rhgb quiet fips=1

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.

SI-2(c)

The Installed Operating System Is Vendor Supported and Certified

The installed operating system must be maintained and certified by a vendor. Red Hat Enterprise Linux is supported by Red Hat, Inc. As the Red Hat Enterprise Linux vendor, Red Hat, Inc. is responsible for providing security patches as well as meeting and maintaining goverment certifications and standards.

An operating system is considered "supported" if the vendor continues to provide security patches for the product as well as maintain government certification requirements. With an unsupported release, it will not be possible to resolve security issue discovered in the system software as well as meet government certifications.

AC-6

Verify and Correct File Permissions with RPM

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions which can be found with

    $ rpm -Va | grep '^.M'

, 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

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.

CM-6(d)

Verify and Correct File Permissions with RPM

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions which can be found with

    $ rpm -Va | grep '^.M'

, 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

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.

SI-7

Verify and Correct File Permissions with RPM

The RPM package management system can check file access permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions which can be found with

    $ rpm -Va | grep '^.M'

, 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

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.

AC-6

Verify and Correct Ownership with RPM

The RPM package management system can check file ownership permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions, which can be found with

    rpm -Va | grep "^.....\(U\|.G\)"

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 --setugids PACKAGENAME

Ownership of binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.

CM-6(d)

Verify and Correct Ownership with RPM

The RPM package management system can check file ownership permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions, which can be found with

    rpm -Va | grep "^.....\(U\|.G\)"

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 --setugids PACKAGENAME

Ownership of binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.

SI-7

Verify and Correct Ownership with RPM

The RPM package management system can check file ownership permissions of installed software packages, including many that are important to system security. After locating a file with incorrect permissions, which can be found with

    rpm -Va | grep "^.....\(U\|.G\)"

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 --setugids PACKAGENAME

Ownership of binaries and configuration files that is incorrect could allow an unauthorized user to gain privileges that they should not have. The ownership set by the vendor should be maintained. Any deviations from this baseline should be investigated.

CM-6(d)

Verify File Hashes with RPM

The RPM package management system can check the hashes of installed software packages, including many that are important to system security. 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 | 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

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.

SI-7

Verify File Hashes with RPM

The RPM package management system can check the hashes of installed software packages, including many that are important to system security. 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 | 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

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.

SC-28

Install Virus Scanning Software

Install virus scanning software, which uses signatures to search for the presence of viruses on the filesystem. The McAfee VirusScan Enterprise for Linux virus scanning tool is provided for DoD systems. Ensure virus definition files are no older than 7 days, or their last release. Configure the virus scanning software to perform scans dynamically on all accessed files. If this is not possible, configure the system to scan all altered files on the system on a daily basis. If the system processes inbound SMTP mail, configure the virus scanner to scan all received mail.

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.

SI-3

Install Virus Scanning Software

Install virus scanning software, which uses signatures to search for the presence of viruses on the filesystem. The McAfee VirusScan Enterprise for Linux virus scanning tool is provided for DoD systems. Ensure virus definition files are no older than 7 days, or their last release. Configure the virus scanning software to perform scans dynamically on all accessed files. If this is not possible, configure the system to scan all altered files on the system on a daily basis. If the system processes inbound SMTP mail, configure the virus scanner to scan all received mail.

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.

SC-7

Install Intrusion Detection Software

The base Red Hat 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.
In DoD environments, supplemental intrusion detection tools, such as, the McAfee Host-based Security System, are available to integrate with existing infrastructure. When these supplemental tools interfere with the proper functioning of SELinux, SELinux takes precedence.

Host-based intrusion detection tools provide a system-level defense when an intruder gains access to a system or network.

CM-3(d)

Install AIDE

Install the AIDE package with the command:

    $ sudo yum install aide

The AIDE package must be installed if it is to be available for integrity checking.

CM-3(e)

Install AIDE

Install the AIDE package with the command:

    $ sudo yum install aide

The AIDE package must be installed if it is to be available for integrity checking.

CM-6(d)

Install AIDE

Install the AIDE package with the command:

    $ sudo yum install aide

The AIDE package must be installed if it is to be available for integrity checking.

SC-28

Install AIDE

Install the AIDE package with the command:

    $ sudo yum install aide

The AIDE package must be installed if it is to be available for integrity checking.

SI-7

Install AIDE

Install the AIDE package with the command:

    $ sudo yum install aide

The AIDE package must be installed if it is to be available for integrity checking.

CM-3(d)

Configure Periodic Execution of AIDE

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

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

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

CM-3(e)

Configure Periodic Execution of AIDE

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

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

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

CM-6(d)

Configure Periodic Execution of AIDE

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

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

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

SC-28

Configure Periodic Execution of AIDE

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

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

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

SI-7

Configure Periodic Execution of AIDE

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

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

By default, AIDE does not install itself for periodic execution. Periodically running AIDE is necessary to reveal unexpected changes in installed files.

CM-3(d)

Build and Test AIDE Database

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.

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.

CM-3(e)

Build and Test AIDE Database

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.

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.

CM-6(d)

Build and Test AIDE Database

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.

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.

SC-28

Build and Test AIDE Database

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.

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.

SI-7

Build and Test AIDE Database

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.

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.

CM-6(d)

Disable Prelinking

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

Because the prelinking feature changes binaries, it can interfere with the operation of certain software and/or modes such as AIDE, FIPS, etc.

SC-28

Disable Prelinking

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

Because the prelinking feature changes binaries, it can interfere with the operation of certain software and/or modes such as AIDE, FIPS, etc.

SI-7

Disable Prelinking

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

Because the prelinking feature changes binaries, it can interfere with the operation of certain software and/or modes such as AIDE, FIPS, etc.

AC-11(b)

Implement Blank Screensaver

Run the following command to set the screensaver mode in the GNOME desktop to a blank screen:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gnome-screensaver/mode blank-only

Setting the screensaver mode to blank-only conceals the contents of the display from passersby.

AC-11(a)

Enable Screen Lock Activation After Idle Period

Run the following command to activate locking of the screensaver in the GNOME desktop when it is activated:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gnome-screensaver/lock_enabled true

Enabling the activation of the screen lock after an idle period ensures password entry will be required in order to access the system, preventing access by passersby.

AC-11(a)

GNOME Desktop Screensaver Mandatory Use

Run the following command to activate the screensaver in the GNOME desktop after a period of inactivity:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gnome-screensaver/idle_activation_enabled true

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.

AC-6

Set GNOME Screen Locking Keybindings

Run the following command to prevent changes to the screensaver lock keybindings:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gnome_settings_daemon/keybindings/screensaver "<Control><Alt>l"

The ability to lock graphical desktop sessions manually allows users to easily secure their accounts should they need to depart from their workstations temporarily.

AC-11(a)

Set GNOME Login Inactivity Timeout

Run the following command to set the idle time-out value for inactivity in the GNOME desktop to minutes:

    $ sudo gconftool-2 \
      --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type int \
      --set /desktop/gnome/session/idle_delay

Setting the idle delay controls when the screensaver will start, and can be combined with screen locking to prevent access from passersby.

AC-19(a)

Disable GNOME Automounting

The system's default desktop environment, GNOME, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. Disable automount and autorun within GNOME by running the following:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_automount false
    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_autorun_never true

Disabling automatic mounting in GNOME can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

AC-19(d)

Disable GNOME Automounting

The system's default desktop environment, GNOME, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. Disable automount and autorun within GNOME by running the following:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_automount false
    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_autorun_never true

Disabling automatic mounting in GNOME can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

AC-19(e)

Disable GNOME Automounting

The system's default desktop environment, GNOME, will mount devices and removable media (such as DVDs, CDs and USB flash drives) whenever they are inserted into the system. Disable automount and autorun within GNOME by running the following:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_automount false
    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/nautilus/preferences/media_autorun_never true

Disabling automatic mounting in GNOME can prevent the introduction of malware via removable media. It will, however, also prevent desktop users from legitimate use of removable media.

CM-7

Disable All GNOME Thumbnailers

The system's default desktop environment, GNOME, uses a number of different thumbnailer programs to generate thumbnails for any new or modified content in an opened folder. The following command can disable the execution of these thumbnail applications:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /desktop/gnome/thumbnailers/disable_all true

This effectively prevents an attacker from gaining access to a system through a flaw in GNOME's Nautilus thumbnail creators.

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.

AC-6

Disable Ctrl-Alt-Del Reboot Key Sequence in GNOME

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, run the following:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type string \
      --set /apps/gnome_settings_daemon/keybindings/power ""

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.

CM-6(b)

Disable GDM Guest Login

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

Failure to restrict system access to authenticated users negatively impacts operating system security.

AC-6

Disable the GNOME Login Restart and Shutdown Buttons

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 shutdown or restart the system. This functionality should be disabled by running the following:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gdm/simple-greeter/disable_restart_buttons true

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.

CM-6(b)

Disable GDM Automatic Login

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

Failure to restrict system access to authenticated users negatively impacts operating system security.

AC-23

Disable the User List

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.
Run the following command to disable the user list:

    $ sudo gconftool-2 --direct \
      --config-source xml:readwrite:/etc/gconf/gconf.xml.mandatory \
      --type bool \
      --set /apps/gdm/simple-greeter/disable_user_list true

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.

SI-7

Ensure gpgcheck Enabled In Main Yum Configuration

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

Ensuring the validity of packages' cryptographic signatures prior to installation ensures the authenticity of the software and protects against malicious tampering.

MA-1(b)

Ensure gpgcheck Enabled In Main Yum Configuration

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

Ensuring the validity of packages' cryptographic signatures prior to installation ensures the authenticity of the software and protects against malicious tampering.

SI-2

Ensure Software Patches Installed

If the system is joined to the Red Hat Network, a Red Hat Satellite Server, 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 Red Hat Network and installed using `rpm`.

Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities.

MA-1(b)

Ensure Software Patches Installed

If the system is joined to the Red Hat Network, a Red Hat Satellite Server, 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 Red Hat Network and installed using `rpm`.

Installing software updates is a fundamental mitigation against the exploitation of publicly-known vulnerabilities.

SI-7

Ensure Red Hat GPG Key Installed

To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG key must properly be installed. To install the Red Hat GPG key, run:

    $ sudo subscription-manager register

If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG key from trusted media such as the Red Hat 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

The Red Hat GPG key is necessary to cryptographically verify packages are from Red Hat.

MA-1(b)

Ensure Red Hat GPG Key Installed

To ensure the system can cryptographically verify base software packages come from Red Hat (and to connect to the Red Hat Network to receive them), the Red Hat GPG key must properly be installed. To install the Red Hat GPG key, run:

    $ sudo subscription-manager register

If the system is not connected to the Internet or an RHN Satellite, then install the Red Hat GPG key from trusted media such as the Red Hat 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

The Red Hat GPG key is necessary to cryptographically verify packages are from Red Hat.

SI-7

Ensure gpgcheck Enabled For All Yum Package Repositories

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

Ensuring all packages' cryptographic signatures are valid prior to installation ensures the authenticity of the software and protects against malicious tampering.

MA-1(b)

Ensure gpgcheck Enabled For All Yum Package Repositories

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

Ensuring all packages' cryptographic signatures are valid prior to installation ensures the authenticity of the software and protects against malicious tampering.

SC-13

Encrypt Partitions

Red Hat Enterprise Linux 6 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=ext3 --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 Red Hat Documentation web site:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/chap-Security_Guide-Encryption.html#sect-Security_Guide-LUKS_Disk_Encryption

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.

SC-28

Encrypt Partitions

Red Hat Enterprise Linux 6 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=ext3 --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 Red Hat Documentation web site:
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Security_Guide/chap-Security_Guide-Encryption.html#sect-Security_Guide-LUKS_Disk_Encryption

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.

SC-32

Ensure /home Located On Separate Partition

If user home directories will be stored locally, create a separate partition for `/home` at installation time (or migrate it later using LVM). If `/home` will be mounted from another system such as an NFS server, then creating a separate partition is not necessary at installation time, and the mountpoint can instead be configured later.

Ensuring that `/home` is mounted on its own partition enables the setting of more restrictive mount options, and also helps ensure that users cannot trivially fill partitions used for log or audit data storage.

SC-32

Ensure /tmp Located On Separate Partition

The `/tmp` directory is a world-writable directory used for temporary file storage. Ensure it has its own partition or logical volume at installation time, or migrate it using LVM.

The `/tmp` partition is used as temporary storage by many programs. Placing `/tmp` in its own partition enables the setting of more restrictive mount options, which can help protect programs which use it.

SC-32

Ensure /var Located On Separate Partition

The `/var` directory is used by daemons and other system services to store frequently-changing data. Ensure that `/var` has its own partition or logical volume at installation time, or migrate it using LVM.

Ensuring that `/var` is mounted on its own partition enables the setting of more restrictive mount options. This helps protect system services such as daemons or other programs which use it. It is not uncommon for the `/var` directory to contain world-writable directories installed by other software packages.

AU-4

Ensure /var/log/audit Located On Separate Partition

Audit logs are stored in the `/var/log/audit` directory. Ensure that it has its own partition or logical volume at installation time, or migrate it later using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Placing `/var/log/audit` in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

AU-9

Ensure /var/log/audit Located On Separate Partition

Audit logs are stored in the `/var/log/audit` directory. Ensure that it has its own partition or logical volume at installation time, or migrate it later using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Placing `/var/log/audit` in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

SC-32

Ensure /var/log/audit Located On Separate Partition

Audit logs are stored in the `/var/log/audit` directory. Ensure that it has its own partition or logical volume at installation time, or migrate it later using LVM. Make absolutely certain that it is large enough to store all audit logs that will be created by the auditing daemon.

Placing `/var/log/audit` in its own partition enables better separation between audit files and other files, and helps ensure that auditing cannot be halted due to the partition running out of space.

AU-9 | Ensure /var/log Located On Separate Partition | System logs are stored in the `/var/log` directory. Ensure that it has its own partition or logical volume at installation time, or migrate it using LVM. | Placing `/var/log` in its own partition enables better separation between log files and other files in `/var/`. |
SC-32 | Ensure /var/log Located On Separate Partition | System logs are stored in the `/var/log` directory. Ensure that it has its own partition or logical volume at installation time, or migrate it using LVM. | Placing `/var/log` in its own partition enables better separation between log files and other files in `/var/`. |