如何保障WordPress网站安全？

function custom_password_policy( $password ) {
    if ( strlen( $password ) < 8 ) {
        return new WP_Error( 'password_too_short', 'Password is too short. It must be at least 8 characters long.' );
    }
    if ( !preg_match( "/[a-z]/", $password ) ) {
        return new WP_Error( 'password_no_lowercase', 'Password must include a lowercase letter.' );
    }
    if ( !preg_match( "/[A-Z]/", $password ) ) {
        return new WP_Error( 'password_no_uppercase', 'Password must include an uppercase letter.' );
    }
    if ( !preg_match( "/[0-9]/", $password ) ) {
        return new WP_Error( 'password_no_number', 'Password must include a number.' );
    }
    return $password;
}

add_filter( 'user_profile_update_errors', 'custom_password_policy' );

function change_admin_username( $user_login, $user ) {
    if ( $user->user_login == 'admin' ) {
        $new_username = 'new_admin_username';
        wp_update_user( array( 'ID' => $user->ID, 'user_login' => $new_username ) );
    }
}

add_action( 'wp_login', 'change_admin_username', 10, 2 );

<FilesMatch "(wp-config.php|xmlrpc.php|wp-admin)">
    Order allow,deny
    Deny from all
</FilesMatch>