A file integrity tool must verify the baseline operating system configuration at least weekly.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-71973	RHEL-07-020030	SV-86597r1_rule		Medium

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

Description

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

STIG	Date
Red Hat Enterprise Linux 7 Security Technical Implementation Guide	2017-07-08

Details

Check Text ( C-72205r1_chk )
Verify the operating system routinely checks the baseline configuration for unauthorized changes. Note: A file integrity tool other than Advanced Intrusion Detection Environment (AIDE) may be used, but the tool must be executed at least once per week. Check to see if AIDE is installed on the system with the following command: # yum list installed aide If AIDE is not installed, ask the SA how file integrity checks are performed on the system. Check for the presence of a cron job running daily or weekly on the system that executes AIDE daily to scan for changes to the system baseline. The command used in the example will use a daily occurrence. Check the "/etc/cron.daily" subdirectory for a "crontab" file controlling the execution of the file integrity application. For example, if AIDE is installed on the system, use the following command: # ls -al /etc/cron.* \| grep aide -rwxr-xr-x 1 root root 29 Nov 22 2015 aide If the file integrity application does not exist, or a "crontab" file does not exist in the "/etc/cron.daily" or "/etc/cron.weekly" subdirectories, this is a finding.

Check Text ( C-72205r1_chk )

Verify the operating system routinely checks the baseline configuration for unauthorized changes.

Note: A file integrity tool other than Advanced Intrusion Detection Environment (AIDE) may be used, but the tool must be executed at least once per week.

Check to see if AIDE is installed on the system with the following command:

# yum list installed aide

If AIDE is not installed, ask the SA how file integrity checks are performed on the system.

Check for the presence of a cron job running daily or weekly on the system that executes AIDE daily to scan for changes to the system baseline. The command used in the example will use a daily occurrence.

Check the "/etc/cron.daily" subdirectory for a "crontab" file controlling the execution of the file integrity application. For example, if AIDE is installed on the system, use the following command:

# ls -al /etc/cron.* | grep aide
-rwxr-xr-x 1 root root 29 Nov 22 2015 aide

If the file integrity application does not exist, or a "crontab" file does not exist in the "/etc/cron.daily" or "/etc/cron.weekly" subdirectories, this is a finding.

Fix Text (F-78325r1_fix)
Configure the file integrity tool to automatically run on the system at least weekly. The following example output is generic. It will set cron to run AIDE daily, but other file integrity tools may be used: # cat /etc/cron.daily/aide 0 0 * * * /usr/sbin/aide --check \| /bin/mail -s "aide integrity check run for " root@sysname.mil