Ubuntu OS must be configured so that when passwords are changed or new passwords are established, pwquality must be used.

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. "pwquality" enforces complex password construction configuration and has the ability to limit brute-force attacks on the system.

Satisfies: SRG-OS-000710-GPOS-00160, SRG-OS-000725-GPOS-00180, SRG-OS-000730-GPOS-00190, SRG-OS-000480-GPOS-00225

Verify Ubuntu OS enforces password complexity rules by using the following command:

     $ grep -i enforcing /etc/security/pwquality.conf  
     enforcing = 1  

If "enforcing" is not "1", is commented out, or is missing, this is a finding.

Check for the use of "pwquality" by using the following command:

     $ cat /etc/pam.d/common-password | grep requisite | grep pam_pwquality 
      password     requisite     pam_pwquality.so retry=3  

If "retry" is set to "0" or is greater than "3", or is missing, this is a finding.

Configure Ubuntu OS to enforce password complexity rules.

Add or modify the following line in the "/etc/security/pwquality.conf" file:

enforcing = 1

Add or modify the following line in the "/etc/pam.d/common-password" file:

password requisite pam_pwquality.so retry=3

Note: The value of "retry" should be between "1" and "3".