base vbulletin vulnerablities , whenever is sported by vbulletin staff here or in .com , are fixed right away or a tracker issue is reported next to it.
Other than that , if u use any modification which has any kind of exploit , what will the staff here can do , so first always before using a modification , always use modifications which are in here , as supported. DO not install unsuported modifications say like beta , or any other things....
Also before installing any modification , you should always try it on a demo site and play with it , check it's templates , hook system and what more you can do with it.
And also , hackers as i know , tends to have knowledge about your server. Most of the time , there is an exploit which happens to your server, which gets exploited by hackers to use.
and also , do not allow xml or html scripts to be uploaded to your server directly and they should not be executed.
much writting ..... hands in pain.
And aswell : Thanks vb.org Staff or helping us .

you guys are goooood.