Cis GCP Cos 5.2.1

5.2.1 Ensure password creation requirements are configured (Automated)

Description

The pam_passwdqc.so module checks the strength of passwords. It performs checks such as making sure a password is not a dictionary word, it is a certain length, contains a mix of characters (e.g. alphabet, numeric, other) and more based on the following options set in the /etc/security/passwdqc.conf:

• min=disabled,disabled,disabled,disabled,14 - The password must be 14 characters or more and consists of four character classes.
• max=40 - The maximum allowed password length is 40.
• passphrase=3 - The number of words required for a passphrase is at least 3.
• match=4 - The length of common substring required to conclude that a password is at least partially based on information found in a character string is 4.
• similar=deny - The password that is similar to the old one is going to be denied.
• random=47 - The size of randomly-generated passphrases in bits is 47.
• enforce=everyone - Warn everyone for weak passwords.
• retry=3 - Let the user provide a password 3 times if the user fails to provide a sufficiently strong password and enter it twice the first time.

For more details, refer to pam_passwdqc module documentation. The settings shown above are one possible policy. Alter these values to conform to your own organization's password policies.

Rationale

Strong passwords protect systems from being hacked through brute force methods.

Audit Procedure

Verify password creation requirements conform to organization policy in /etc/security/passwdqc.conf with the following command.

# cat /etc/security/passwdqc.conf

min=disabled,disabled,disabled,disabled,14
max=40
passphrase=3
match=4
similar=deny
random=47
enforce=everyone
retry=3

Run the following command and verify that the output is similar to:

grep  pam_passwdqc.so /etc/pam.d/system-auth
password       required       pam_passwdqc.so config=/etc/security/passwdqc.conf

Expected Result

The /etc/security/passwdqc.conf file should contain password complexity settings conforming to site policy. The pam_passwdqc.so module should be configured in /etc/pam.d/system-auth.

Remediation

Edit the file /etc/security/passwdqc.conf and add or modify the following lines for password length and complexity to conform to site policy:

min=disabled,disabled,disabled,disabled,14
max=40
passphrase=3
match=4
similar=deny
random=47
enforce=everyone
retry=3

Edit the /etc/pam.d/system-auth files to include the appropriate options for pam_passwdqc.so and to conform to site policy:

password       required       pam_passwdqc.so config=/etc/security/passwdqc.conf

Additional Information:

Consult your documentation for the appropriate PAM file and module.

Additional module options may be set, recommendation requirements only cover including try_first_pass and minlen set to 14 or more.

Settings in /etc/security/pwquality.conf must use spaces around the = symbol.

CIS Controls

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• Level 2 - Server