Enrico Sorcinelli

JSON REST API and XML-RPC API are powerful ways to remotely interact with WordPress.
If you don’t have external applications that need to communicate with your WordPress instance using JSON REST API or XML-RPC API you should disable access to them for external requests.
In the standard WordPress installation JSON REST API and XML-RPC API are enabled by default. 
In particular the REST API is turned on also for unlogged users. This means that your WordPress instance is potentially leaking data, for example anyone could be able to:
<ul>
<li>copy easily your published contents natively with the REST API (and not with a web crawler);</li>
<li>get the list of all users (with their ID, nickname and name);</li>
<li>retrieve other information that you didn’t want to be public (such as an unlisted published page or a saved media not yet used).</li>
</ul>
Even if you could do the stuff by writing your own code using native filters, this plugin aims to help you to control JSON REST API and XML-RPC API accesses from the administration panel or programmatically by a simple API filter.
<h3>Basic Features</h3>
<ul>
<li>Disable REST API interface for unlogged users.</li>
<li>Disable JSONP support on REST API.</li>
<li>Add Basic Authentication to REST API.</li>
<li>Remove REST <code><link></code> tags, REST <code>Link</code> HTTP header and REST Really Simple Discovery (RSD) informations.</li>
<li>Setup trusted users, IP/Networks and endpoints for unlogged users REST requests.</li>
<li>Change REST endpoint prefix.</li>
<li>Disable XML-RPC API interface.</li>
<li>Remove <code><link></code> to the Really Simple Discovery (RDS) informations.</li>
<li>Remove <code>X-Pingback</code> HTTP header.</li>
<li>Setup trusted users, IP/Networks and methods for XML-RPC requests.</li>
<li>Show user’s access informations in users list administration screen.</li>
</ul>
<h3>Usage</h3>
Once the plugin is installed you can control settings in the following ways:
<ul>
<li>Using the Settings->REST XML-RPC Data Checker administration screen.</li>
<li>Programmatically, by using <code>rest_xmlrpc_data_checker_settings</code> filter (see below).</li>
</ul>
<h3>API</h3>
<h4>Hooks</h4>
<code>rest_xmlrpc_data_checker_settings</code>
Filters plugin settings values.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_settings', array $settings )
</code></pre>
<code>rest_xmlrpc_data_checker_admin_settings</code>
Filter allowing to display or not the plugin settings page in the administration.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_admin_settings', boolean $display )
</code></pre>
<code>rest_xmlrpc_data_checker_rest_error</code>
Filter JSON REST authentication error after plugin checks.
<pre><code>apply_filters( 'rest_xmlrpc_data_checker_rest_error', WP_Error|boolean $result )
</code></pre>
<code>xmlrpc_before_insert_post</code>
Filter XML-RPC post data to be inserted via XML-RPC before to insert post into database.
<pre><code>apply_filters( 'xmlrpc_before_insert_post', array|IXR_Error $content_struct, WP_User $user )
</code></pre>

REST XML-RPC Data Checker

REST XML-RPC Data Checker allow to check JSON REST and XML-RPC API requests and grant access permissions.

Lars Koudal

cleverplugins

Prevent your WordPress site from participating and being a victim of pingback denial of service attacks. After activation the plugin automatically disables XML-RPC. There’s no need to configure anything.
By disabling the XML-RPC pingback you’ll: 
* lower your server CPU usage 
* prevent malicious scripts from using your site to run pingback denial of service attacks 
* prevent malicious scripts to run denial of service attacks on your site via pingback
From sucuri.net:
<blockquote>
Any WordPress site with Pingback enabled (which is on by default) can be used in DDOS attacks against other sites.
</blockquote>
<h4>Learn More</h4>
<ul>
<li><a href="http://wptavern.com/how-to-prevent-wordpress-from-participating-in-pingback-denial-of-service-attacks" rel="nofollow ugc">How To Prevent WordPress From Participating In Pingback Denial of Service Attacks</a> – wptavern.com</li>
<li><a href="http://blog.sucuri.net/2014/03/more-than-162000-wordpress-sites-used-for-distributed-denial-of-service-attack.html" rel="nofollow ugc">More Than 162,000 WordPress Sites Used for Distributed Denial of Service Attack</a> – sucuri.net</li>
<li><a href="http://hackguard.com/xmlrpc-php-ping-backs-hackers-denial-service-attacks" rel="nofollow ugc">xmlrpc.php and Pingbacks and Denial of Service Attacks, Oh My!</a> – hackguard.com</li>
</ul>
<h4>Is Your Site Attacking Others?</h4>
Use <a href="http://labs.sucuri.net/?is-my-wordpress-ddosing" rel="nofollow ugc">Sucuri’s WordPress DDOS Scanner</a> to check if your site is DDOS’ing other websites
<h4>Why Not Just Disable XMLRPC Altogether?</h4>
Yes, you can choose to do that, but if you use popular plugins like JetPack (that use XMLRPC) then those plugins will stop working. That is why this small plugin exists.

Remove & Disable XML-RPC Pingback

Great plugin, super easy to install and just sits there doing it's job. Very light as well, so has no effects that I could see, on site speed or memory usage. Can't think of a reason why you wouldn't be using this to be honest. Thanks for developing it!

Just what I needed

Prevent pingback, XML-RPC and denial of service DDOS attacks by disabling the XML-RPC pingback functionality.

REST XML-RPC Data Checker vs Remove & Disable XML-RPC Pingback