WordPress uses XML-RPC as a protocol to establish communication between different systems, allowing other external applications like desktop clients and other blogging platforms to connect with WordPress. XML-RPC has been a crucial part of WordPress since its inception, contributing to seamless integration with the rest of the digital world.
But XML-RPC’s protocol implementation in WordPress through the xmlrpc.php file has certain limitations. xmlrpc.php could compromise the security of your WordPress site and has now been replaced by the advanced and secure WordPress REST API, which also supports WordPress’ communication with other applications.
This article will discuss what the xmlrpc.php file is, why it’s beneficial to disable it for better website security, and how to check if it’s currently active on your WordPress site.
What is the xmlrpc.php file?
XML-RPC facilitates the communication between WordPress and other systems by standardizing the interactions through HTTP for transport and XML for encoding. WordPress evolved from b2 blogging software, where XML-RPC was first introduced. The xmlrpc.php file stores the code for this system in the root directory of a WordPress website, even though XML-RPC has now become largely outdated.
Contents of xmlrpc.php file In earlier versions of WordPress, XML-RPC was disabled by default. However, from version 3.5 onwards, it was enabled by default to facilitate communication between the WordPress mobile app and WordPress installations. Before this version, users had to enable XML-RPC on their websites for the mobile app to post content as a separate entity, communicating with the WordPress site via xmlrpc.php.
XML-RPC not only allowed mobile apps to work but also facilitated communication between WordPress and other blogging platforms enabled trackbacks and pingbacks, and powered the Jetpack plugin. However, with the integration of the REST API into WordPress core, the use of xmlrpc.php for communication has become obsolete.
Due to the REST API’s more extensive capabilities and its replacement of XML-RPC, it is now recommended to disable xmlrpc.php on your website to mitigate risk.
Reasons to disable xmlrpc.php on WordPress
With the advent of the REST API, XML-RPC is no longer required for external communication in WordPress, making it advisable to disable it as it could introduce security vulnerabilities and become the target of various attacks.
Let’s explore the specific vulnerabilities associated with the xmlrpc.php file.
Brute force via xmlrpc.php
Hackers can exploit the xmlrpc.php file by attempting to gain access to the website’s backend with thousands of username and password combinations through brute force attacks. Websites with weak admin passwords and lacking multi-factor authentication are particularly vulnerable to such attacks.
Hackers use automated tools to find and list all valid usernames for a website and then exploit the xmlrpc.php file to carry out brute force attacks by sending requests with various password combinations. Inadequate website security measures may allow hackers to gain unauthorized access to your site, which could pose a significant security risk to your WordPress environment.
Therefore, if you are using a version of WordPress that uses the REST API for communication with external systems, it is wise to disable XML-RPC entirely to mitigate risk.
DDoS attacks via xmlrpc.php
Distributed Denial of Service (DDoS) attacks can completely incapacitate your server by sending thousands of simultaneous requests. In WordPress, hackers often use the pingback feature along with the xmlrpc.php file to execute DDoS attacks. These attacks can overload your server and take your site offline by sending a massive number of pingbacks through xmlrpc.php in a short time.
To initiate the attack, hackers first identify a target page and verify the presence of the xmlrpc.php file by sending a specific request. Once they confirm its existence, they start bombarding it with pingback requests from a network of compromised websites.
If you have determined that xmlrpc.php is currently active on your WordPress website, it is recommended that you disable it to improve your website’s security. Here’s how to disable xmlrpc.php in WordPress.
Disabling xmlrpc.php – nginx
Add the following location block to nginx.conf, adding a new allow line for each IP allowed to access it.
location = /xmlrpc.php {
allow 192.0.0.1;
deny all;
}If you don’t want to whitelist by IP, you can add some logic to the location block to allow a useragent:
if ($http_user_agent !~* ""WordPress") {
return 403;
}Disabling xmlrpc.php – Apache
There are several ways to disable xmlrpc.php in WordPress. The first method is to add a few lines of code to your site’s .htaccess file. Here are the steps:
- Access your website’s root directory using FTP or your hosting provider’s file manager.
- Look for the .htaccess file and download a copy to your computer for backup.
- Open the .htaccess file using a text editor.
- Add the following lines of code to the file:
# Block WordPress xmlrpc.php requests
<Files xmlrpc.php>
order deny,allow
deny from all
</Files>- Save the .htaccess file and upload it back to your website’s root directory, replacing the existing file.
Once you have completed these steps, xmlrpc.php will be disabled on your WordPress website. You can test whether the file has been disabled by using the curl command again to check the XML-RPC endpoint.
Using a plugin
There are several plugins available in the WordPress repository that can disable xmlrpc.php with just a few clicks. Some popular plugins include Disable XML-RPC, WP Disable, and Jetpack.
While xmlrpc.php was an essential part of WordPress in the past, it has now become outdated and poses a significant security risk to your website. By disabling it, you can protect your website from brute force attacks and DDoS attacks. We hope that this article has been helpful in understanding what xmlrpc.php is and how to disable it on your WordPress website.
