Information
The pwquality difok option sets the number of characters in a password that must not be present in the old password.
Use of a complex password helps to increase the time and resources required to compromise the password. Password complexity, or strength, is a measure of the effectiveness of a password in resisting attempts at guessing and brute-force attacks.
Password complexity is one factor of several that determines how long it takes to crack a password. The more complex the password, the greater the number of possible combinations that need to be tested before the password is compromised.
Solution
Create or modify a file ending inconf in the /etc/security/pwquality.conf.d/ directory or the file /etc/security/pwquality.conf and add or modify the following line to set difok to 2 or more. Ensure setting conforms to local site policy:
difok = 2
Example:
# sed -ri 's/^s*difoks*=/# &/' /etc/security/pwquality.conf
# printf '
%s' "difok = 2" >> /etc/security/pwquality.conf.d/50-pwdifok.conf
- OR - If the pam-config tool has been used to configure the global PAM configuration files:
Run the following command to add the difok option to 2 or more and follows local site policy
# pam-config -a --cracklib-difok=2
Note:
- The difok option maybe set to 2 or more and depending on local site policy.
- Best practice for updating pam modules is to configure settings in aconf file in the /etc/security/pwquality.conf.d/ directory or /etc/security/pwquality.conf