WordPress.com Uses LiteSpeed and Nginx
There have been some rumors spreading about WordPress.com switching over to Nginx from Litespeed and discontinuing the use of Litespeed web server. If you view the server headers that are returned from WordPress.com, you will see it uses Nginx as the front end.
A code vulnerability was released that allowed a bad request to be sent to any server running Litespeed and it would show the source code of PHP pages. It has been patched since, but the response from a bad server request returns a “400 Bad Request” which also shows the web server used.
If you just sent the bad request to the servers at WordPress.com, you will get the error: http://wordpress.com/index.php%00.txt
A few months ago I wrote this article on my other blog (which has been changed to my personal blog) and I wanted to put the same article here.