AIX /etc/security/mkuser.sys.custom file must not exist unless it is needed for customizing a new user account.

The "/etc/security/mkuser.sys.custom" is called by "/etc/security/mkuser.sys" to customize the new user account when a new user is created, or a user is logging into the system without a home directory. An improper "/etc/security/mkuser.sys.custom" script increases the risk that non-privileged users may obtain elevated privileges. It must not exist unless it is needed.

Check if the "/etc/security/mkuser.sys.custom" file exists: # ls /etc/security/mkuser.sys.custom

If the above command shows the file exists, this is a finding.

Remove the "/etc/security/mkuser.sys.custom" file using the following command:

# rm /etc/security/mkuser.sys.custom