The system must require passwords to contain at least one lower-case alphabetic character.

From Red Hat Enterprise Linux 6 Security Technical Implementation Guide

Associated with: CCI-000193

SV-50372r3_rule The system must require passwords to contain at least one lower-case alphabetic character.

Vulnerability discussion

Requiring a minimum number of lower-case characters makes password guessing attacks more difficult by ensuring a larger search space.

Check content

To check how many lower-case characters are required in a password, run the following command: $ grep pam_cracklib /etc/pam.d/system-auth /etc/pam.d/password-auth Note: The "lcredit" parameter (as a negative number) will indicate how many lower-case characters are required. The DoD requires at least one lower-case character in a password. This would appear as "lcredit=-1". If “lcredit” is not found or not set to the required value, this is a finding.

Fix text

The pam_cracklib module's "lcredit=" parameter controls requirements for usage of lower-case letters in a password. When set to a negative number, any password will be required to contain that many lower-case characters. Edit /etc/pam.d/system-auth and /etc/pam.d/password-auth adding "lcredit=-1" after pam_cracklib.so to require use of a lower-case character in passwords.

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