Disable pingback.ping xmlrpc method to prevent Wordpress from participating in DDoS attacks.

wp-config.php

//  Disable pingback.ping xmlrpc method to prevent WordPress from participating in DDoS attacks

// remove x-pingback HTTP header
add_filter('wp_headers', function($headers) {
    unset($headers['X-Pingback']);
    return $headers;
});
// disable pingbacks
add_filter( 'xmlrpc_methods', function( $methods ) {
        unset( $methods['pingback.ping'] );
        return $methods;
});
add_filter( 'auto_update_translation', '__return_false' );