5.3.3 Ensure password reuse is limited - system-auth
Information
Forcing users not to reuse their past 5 passwords make it less likely that an attacker will be able to guess the password. Note that these change only apply to accounts configured on the local system.
Solution
Edit the /etc/pam.d/password-auth and /etc/pam.d/system-auth files to include the remember option and conform to site policy as shown: password sufficient pam_unix.so remember=5