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 if the Ubuntu operating system generates audit records when successful/unsuccessful attempts to use the "su" command occur.

Check the configured audit rules with the following commands:

# sudo auditctl -l | grep '/bin/su'

-a always,exit -F path=/bin/su -F perm=x -F auid>=1000 -F auid!=-1 -k privileged-priv_change

If the command does not return lines that match the example or the lines are commented out, this is a finding.

Note: The '-k' allows for specifying an arbitrary identifier and the string after it does not need to match the example output above.

Fix

Configure the Ubuntu operating system to generate audit records when successful/unsuccessful attempts to use the "su" command occur.

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

-a always,exit -F path=/bin/su -F perm=x -F auid>=1000 -F auid!=4294967295 -k privileged-priv_change

In order to reload the rules file, issue the following command:

# sudo augenrules --load

Note:
The "root" account must be used to view/edit any files in the /etc/audit/rules.d/ directory.