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V-268170

CAT II (Medium)

NixOS must enable the use of pwquality.

Rule ID

SV-268170r1131146_rule

STIG

Anduril NixOS Security Technical Implementation Guide

Version

V1R2

CCIs

CCI-000366

Discussion

If the operating system allows the user to select passwords based on dictionary words, then this increases the chances of password compromise by increasing the opportunity for successful guesses and brute-force attacks.

Check Content

Verify NixOS prevents the use of dictionary words for passwords with the following command:

$ grep -i pam_pwquality /etc/pam.d/passwd /etc/pam.d/chpasswd /etc/pam.d/sudo

/etc/pam.d/passwd:password requisite /nix/store/db96zr26w71dzx0bzf47d88kw19fr0l7-libpwquality-1.4.5.-lib/lib/security/pam_pwquality.so
/etc/pam.d/chpasswd:password requisite /nix/store/db96zr26w71dzx0bzf47d88kw19fr0l7-libpwquality-1.4.5.-lib/lib/security/pam_pwquality.so
/etc/pam.d/sudo:password requisite /nix/store/db96zr26w71dzx0bzf47d88kw19fr0l7-libpwquality-1.4.5.-lib/lib/security/pam_pwquality.so

If the pam_pwquality.so module is not present in the passwd, chpasswd, and sudo pam files, this is a finding.

Fix Text

Configure NixOS to check password change attempts against a dictionary.

Add the following Nix code to the NixOS Configuration, usually located in /etc/nixos/configuration.nix or /etc/nixos/flake.nix:

security.pam.services.passwd.text = pkgs.lib.mkDefault (pkgs.lib.mkBefore "password requisite ${pkgs.libpwquality.lib}/lib/security/pam_pwquality.so");
security.pam.services.chpasswd.text = pkgs.lib.mkDefault (pkgs.lib.mkBefore "password requisite ${pkgs.libpwquality.lib}/lib/security/pam_pwquality.so");
security.pam.services.sudo.text = pkgs.lib.mkDefault (pkgs.lib.mkBefore "password requisite ${pkgs.libpwquality.lib}/lib/security/pam_pwquality.so");

Rebuild and switch to the new NixOS configuration:
$ sudo nixos-rebuild switch