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.

Amin Nazemi

Neatma

Protect your website from xmlrpc brute-force attacks,DOS and DDOS attacks, this plugin disables the XML-RPC and trackbacks-pingbacks on your WordPress website.
PLUGIN FEATURES 
(These are options you can enable or disable each one)
<ul>
<li>Disable access to xmlrpc.php file using .httacess file </li>
<li>Automatically change htaccess file permission to read-only (0444)</li>
<li>Disable X-pingback to minimize CPU usage </li>
<li>Disable selected methods from XML-RPC</li>
<li>Remove pingback-ping link from header</li>
<li>Disable trackbacks and pingbacks to avoid spammers and hackers</li>
<li>Rename XML-RPC slug to whatever you want</li>
<li>Black list IPs for XML-RPC</li>
<li>White list IPs for XML-RPC</li>
<li>Some options to speed-up your wordpress website</li>
<li>Disable JSON REST API</li>
<li>Hide WordPress Version</li>
<li>Disable built-in WordPress file editor</li>
<li>Disable wlw manifest</li>
<li>And some other options</li>
</ul>
What is XMLRPC
XML-RPC, or XML Remote Procedure Call is a protocol which uses XML to encode its calls and HTTP as a transport mechanism. 
Beginning in WordPress 3.5, XML-RPC is enabled by default. Additionally, the option to disable/enable XML-RPC was removed. For various reasons, site owners may wish to disable this functionality. This plugin provides an easy way to do so.
Why you should disable XML-RPC 
Xmlrpc has two main weaknesses
<ul>
<li>Brute force attacks: 
Attackers try to login to WordPress using xmlrpc.php with as many username/password combinations as they can enter. A method within xmlrpc.php allows the attacker to use a single command (system.multicall) to guess hundreds of passwords. Daniel Cid at Sucuri described it well in October 2015: “With only 3 or 4 HTTP requests, the attackers could try thousands of passwords, bypassing security tools that are designed to look and block brute force attempts.”</li>
<li>Denial of Service Attacks via Pingback: 
Back in 2013, attackers sent Pingback requests through xmlrpc.php of approximately 2500 WordPress sites to “herd (these sites) into a voluntary botnet,” according to Gur Schatz at Incapsula. “This gives any attacker a virtually limitless set of IP addresses to Distribute a Denial of Service attack across a network of over 100 million WordPress sites, without having to compromise them.”</li>
</ul>

Disable XML-RPC-API

The upgrade notice keeps coming back on every screen even after being dismissed. It looks very unprofessional to my clients and is embarrassing for me as a web developer, i would rather disable the plugin and use the code in a function. 

It should be permanently dismissible via a cookie, like for other plugins. It might be ok once, when the plugin is first installed or updated, but after that, it should never appear again. 

Good plugin, but upgrade nag is too annoying

A simple and lightweight plugin to disable XML-RPC API, X-Pingback and pingback-ping in WordPress 3.5+ for a faster and more secure website

REST XML-RPC Data Checker vs Disable XML-RPC-API