Vulnerability Discussion

Once an attacker establishes access to a system, the attacker often attempts to create a persistent method of reestablishing access. One way to accomplish this is for the attacker to create an account. Auditing account creation actions provides logging that can be used for forensic purposes.

To address access requirements, many operating systems may be integrated with enterprise level authentication/access/auditing mechanisms that meet or exceed access control policy requirements.

Satisfies: SRG-OS-000004-GPOS-00004, SRG-OS-000239-GPOS-00089, SRG-OS-000240-GPOS-00090, SRG-OS-000241-GPOS-00091, SRG-OS-000303-GPOS-00120, SRG-OS-000458-GPOS-00203, SRG-OS-000476-GPOS-00221

Check

Verify the Ubuntu operating system generates audit records for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd".

Check the currently configured audit rules with the following command:

$ sudo auditctl -l | grep opasswd

-w /etc/security/opasswd -p wa -k usergroup_modification

If the command does not return a line that matches the example or the line is 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 for all account creations, modifications, disabling, and termination events that affect "/etc/security/opasswd".

Add or update the following rule to "/etc/audit/rules.d/stig.rules":

-w /etc/security/opasswd -p wa -k usergroup_modification

To reload the rules file, issue the following command:

$ sudo augenrules --load