4.1.3.18 Ensure successful and unsuccessful attempts to use the usermod command are recorded

Information

The operating system must generate audit records for successful/unsuccessful uses of the usermod command.

Without generating audit records that are specific to the security and mission needs of the organization, it would be difficult to establish, correlate, and investigate the events relating to an incident or identify those responsible for one.

Audit records can be generated from various components within the information system (e.g., module or policy filter).

Solution

Create audit rules

Edit or create a file in the /etc/audit/rules.d/ directory, ending inrules extension, with the relevant rules to monitor successful and unsuccessful attempts to use the usermod command.

64 Bit systems

Example:

# {
UID_MIN=$(awk '/^s*UID_MIN/{print $2}' /etc/login.defs)
[ -n "${UID_MIN}" ] && printf "
-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=${UID_MIN} -F auid!=unset -k usermod
" >> /etc/audit/rules.d/50-usermod.rules || printf "ERROR: Variable 'UID_MIN' is unset.
"
}

Load audit rules

Merge and load the rules into active configuration:

# augenrules --load

Check if reboot is required.

# if [[ $(auditctl -s | grep "enabled") =~ "2" ]]; then printf "Reboot required to load rules
"; fi

32 Bit systems

Follow the same procedures as for 64 bit systems and ignore any entries with b64

See Also

https://workbench.cisecurity.org/files/4239