Recently in the server logs I saw lots of attempts to /xmlrpc.php
/xmlrpc.php is the file used for Pingbacks, so if someone links to my blog , they can add my blog article and WordPress will check in then create a link to the users site. This actually opens up wordpress sites to be used for DOS’ people
You can disable access to this file via updating .htaccess
# Block WordPress xmlrpc.php requests
deny from all
Trackback from your site.