The system must require at least four characters be changed between the old and new passwords during a password change.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-22306	GEN000750	SV-38677r1_rule	IAIA-1 IAIA-2	Medium

Description
To ensure password changes are effective in their goals, the system must ensure old and new passwords have significant differences. Without significant changes, new passwords may be easily guessed based on the value of a previously compromised password.

STIG	Date
AIX 5.3 SECURITY TECHNICAL IMPLEMENTATION GUIDE	2014-10-03

Details

Check Text ( C-36906r1_chk )
Check the value of the mindiff parameter. Procedure: #lsuser -a mindiff ALL If any users mindiff is less than 4, this is a finding.

Fix Text (F-32075r1_fix)
Use the chsec command to change mindiff to 4. # chsec -f /etc/security/user -s default -a mindiff=4 # chuser mindiff=4 < user id >