What Is xmlrpc.php in WordPress and Why You Should Disable It

XML-RPC (Remote Procedure Call using XML) is a protocol that enables communication between different systems over HTTP. In the context of WordPress, xmlrpc.php is a file that facilitates XML-RPC communication for various purposes. Here’s a breakdown of its history, usage, and reasons why you might consider disabling it:

History and Usage:

1. Early Days of WordPress: XML-RPC was introduced in the early days of WordPress when internet connections were slow. It allowed users to write content offline and then connect to their WordPress site to publish it.
2. Mobile Access: It enabled remote access, allowing users to connect to their WordPress site via smartphones or other devices.
3. Trackbacks and Pingbacks: XML-RPC facilitated the implementation of trackbacks and pingbacks from other sites.
4. Jetpack Plugin: Some features associated with the Jetpack plugin relied on XML-RPC.
5. Default Status: XML-RPC was initially disabled by default. With WordPress 3.5, it became enabled by default to support the WordPress mobile app.
6. REST API: In 2015, WordPress introduced the REST API, providing an alternative for interacting with mobile applications and other platforms. The REST API largely replaced XML-RPC in many cases.

Reasons to Disable xmlrpc.php:

1. Security Concerns: The major issue with XML-RPC is security. While XML-RPC itself may not be inherently insecure, the xmlrpc.php file can be exploited for brute force attacks on a WordPress site.
2. Brute Force Attacks: Attackers may use XML-RPC to attempt unauthorized access to a site by trying various username and password combinations. This can bypass security tools that typically detect and block brute force attacks.
3. DDoS Attacks: The pingback feature in XML-RPC has been exploited for Distributed Denial of Service (DDoS) attacks. Hackers could use it to send pingbacks to thousands of sites simultaneously, causing a site to go offline.

How to Disable xmlrpc.php:

1. Using Plugins:

• Install a plugin like “Disable XML-RPC-API” from the WordPress Plugin repository.
• Activate the plugin to automatically insert the necessary code to turn off XML-RPC.
• Note: Disabling XML-RPC completely might cause conflicts with some plugins or functionalities.

1. Manual Disabling:

• Open your .htaccess file.
• Add the following code to block XML-RPC requests:
  # Block WordPress xmlrpc.php requests
  <Files xmlrpc.php>
  order deny,allow
  deny from all allow from xxx.xxx.xxx.xxx
  </Files>
• Replace xxx.xxx.xxx.xxx with the IP address you wish to allow access to xmlrpc.php or remove the line completely.

Conclusion:

Disabling xmlrpc.php is often recommended for security reasons, but it’s essential to be cautious, especially if some plugins or functionalities on your site depend on XML-RPC. Assess the specific needs of your site before deciding whether to disable it.