WordPress Plugin: Enable 403 status on login failed

security.php

<?php
/**
* Plugin Name: Security Auth
* Plugin URI: http://kovshenin.com/2014/fail2ban-wordpress-nginx/
* Description: Enable 403 status on login failed.
* Tags: security, login 
* Version: 1.0
* License: GPLv2
* Author: Konstantin Kovshenin
* Author URI: http://kovshenin.com/
*
*/

if ( realpath(__FILE__) === realpath($_SERVER['SCRIPT_FILENAME']) )
    exit('Do not access this file directly.');

function my_login_failed_403() {
    status_header( 403 );
}
add_action( 'wp_login_failed', 'my_login_failed_403' );