Vulnerability Discussion

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).

Check

Verify that an audit event is generated for any successful/unsuccessful use of the "usermod" command.

Check the currently configured audit rules with the following command:

$ sudo auditctl -l | grep -w usermod

-a always,exit -S all -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=-1 -F key=privileged-usermod

If the command does not return a line that matches the example or the line is commented out, this is a finding.

Note: The "key=" value is arbitrary and can be different from the example output above.

Fix

Configure the audit system to generate an audit event for any successful/unsuccessful uses of the "usermod" command.

Add or update the following rules in the "/etc/audit/rules.d/stig.rules" file:

-a always,exit -F path=/usr/sbin/usermod -F perm=x -F auid>=1000 -F auid!=unset -k privileged-usermod

To reload the rules file, issue the following command:

$ sudo augenrules --load

Note: The "-k " at the end of the line gives the rule a unique meaning to help during an audit investigation. The does not need to match the example above.