Level 1 - Server Level 1 - Workstation
The PASS_WARN_AGE parameter in /etc/login.defs allows an administrator to notify users that their password will expire in a defined number of days. It is recommended that the PASS_WARN_AGE parameter be set to 7 or more days.
Providing an advance warning that a password will be expiring gives users time to think of a secure password. Users caught unaware may choose a simple password or write it down where it may be discovered.
Run the following command and verify PASS_WARN_AGE is 7 or more:
# grep PASS_WARN_AGE /etc/login.defs PASS_WARN_AGE 7
Verify all users with a password have their number of days of warning before password expires set to 7 or more:
# egrep ^[^:]+:[^\!*] /etc/shadow | cut -d: -f1 <list of users> # chage --list <user> Number of days of warning before password expires : 7
Set the PASS_WARN_AGE parameter to 7 in /etc/login.defs:
PASS_WARN_AGE 7
Modify user parameters for all users with a password set to match:
# chage --warndays 7 <user>
You can also check this setting in /etc/shadow directly. The 6th field should be 7 or more for all users with a password.