The system must prohibit the reuse of passwords within five iterations.

From Red Hat Enterprise Linux 5 Security Technical Implementation Guide

Associated with IA controls: IAIA-2, IAIA-1

Associated with: CCI-000200

SV-37323r2_rule The system must prohibit the reuse of passwords within five iterations.

Vulnerability discussion

If a user, or root, used the same password continuously or was allowed to change it back shortly after being forced to change it to something else, it would provide a potential intruder with the opportunity to keep guessing at one user's password until it was guessed correctly.

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Fix text

Create the password history file. # touch /etc/security/opasswd # chown root:root /etc/security/opasswd # chmod 0600 /etc/security/opasswd Enable password history. If /etc/pam.d/system-auth references /etc/pam.d/system-auth-ac refer to the man page for system-auth-ac for a description of how to add options not configurable with authconfig. Edit /etc/pam.d/system-auth to include the remember option on any "password pam_unix" or "password pam_history" lines set to at least 5.

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