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). The "useradd" command modifies the system account files to reflect the changes that are specified on the command line.

When a user logs on, the AUID is set to the UID of the account that is being authenticated. Daemons are not user sessions and have the loginuid set to "-1". The AUID representation is an unsigned 32-bit integer, which equals "4294967295". The audit system interprets "-1", "4294967295", and "unset" in the same way.

Satisfies: SRG-OS-000037-GPOS-00015, SRG-OS-000042-GPOS-00020, SRG-OS-000062-GPOS-00031, SRG-OS-000392-GPOS-00172, SRG-OS-000462-GPOS-00206, SRG-OS-000466-GPOS-00210, SRG-OS-000471-GPOS-00215

Check

Verify that OL 9 is configured to audit the execution of the "useradd" command with the following command:

$ sudo auditctl -l | grep useradd

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

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

Fix

Configure OL 9 to generate audit records upon successful/unsuccessful attempts to use the "useradd " command by adding or updating the following rule in "/etc/audit/rules.d/audit.rules":

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

To load the rules to the kernel immediately, use the following command:

$ sudo augenrules --load