On the Hacker Webzine there's a new post pointing out two PHP reconnaissance vectors that can be used to find out more about the remote PHP servers.
I've talked about this if you followed my blog last week. These two vectors can be used to trigger error messages or to obtain more intelligence about the server within PHP. These are not very well known and therefore I wanted to share it here.
One of the vectors has to do with how the developer handles the $_SERVER variables (not sanitized correctly because the developer thinks they can't be changed) and the other deals with changing the PHPSESSID (session ID) to exploit if it is echoed back into the page.