NixOS must enforce a delay of at least four seconds between logon prompts following a failed logon attempt.

Limiting the number of logon attempts over a certain time interval reduces the chances that an unauthorized user may gain access to an account.

Verify NixOS enforces a four-second delay between logon attempts with the following command:

$ grep -I delay /etc/login.defs

FAIL_DELAY 4

If "FAIL_DELAY" is not set to "4" or greater, is commented out, or is missing, this is a finding.

Configure NixOS to enforce a four-second delay between logon attempts.

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

security.loginDefs.settings."FAIL_DELAY" = "4";

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