NixOS must enable the use of pwquality.

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.

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.

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