Swellfire

This plugin disables the XML-RPC API on a WordPress site running 3.5 or above and unsets the X-Pingback header.
Beginning in 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.

Disable XML-RPC & Unset X-Pingback

This plugin disables XML-RPC API in WordPress 3.5+, which is enabled by default.

yehudah

multipie ways to help block xmlrpc attacks.
This plugin have this options:
First Option: 
Log errors and access – to debug plugin errors and access to the xmlrpc file.
The protection options:
<ul>
<li>Disable xmlrpc – disable the file complete with wordpress built in option.</li>
<li>Block login errors ip’s in htaccess – every WRONG login attempt will be blocked inside the htaccess file.</li>
<li>Enable xmlrpc for a specific user – give permission to access the file to pre define user you will choose.</li>
<li>Disable xmlrpc built in functions – xmlrpc have many options and actions to query on your wordpress site, with this option you can choose which option to disable and wich to keep enabled.</li>
</ul>

xmlrpc attacks blocker

multipie ways to help block xmlrpc attacks.

Disable XML-RPC & Unset X-Pingback vs xmlrpc attacks blocker