UBTU-16-010280 - Account identifiers (individuals, groups, roles, and devices) must disabled after 35 days of inactivity.
Inactive identifiers pose a risk to systems and applications because attackers may exploit an inactive identifier and potentially obtain undetected access to the system. Owners of inactive accounts will not notice if unauthorized access to their user account has been obtained. Ubuntu operating systems need to track periods of inactivity and disable application identifiers after 35 days of inactivity.
Configure the Ubuntu operating system to disable account identifiers after 35 days of inactivity after the password expiration. Run the following command to change the configuration for useradd: # sudo useradd -D -f 35 DoD recommendation is 35 days, but a lower value is acceptable. The value '-1' will disable this feature, and '0' will disable the account immediately after the password expires.