Information
The /etc/security/opasswd file stores the users' old passwords and can be checked to ensure that users are not recycling recent passwords. The number of passwords remembered is set via the remember argument value in set for the pam_pwhistory module.
- remember=<N> - <N> is the number of old passwords to remember
Requiring users not to reuse their passwords make it less likely that an attacker will be able to guess the password or use a compromised password.
Note: These change only apply to accounts configured on the local system.
Solution
Run the following command to add the remember option to 24 or more and meets local site policy:
# pam-config -a --pwhistory --pwhistory-remember=24