I've use to use a combination of suPHP with suExec in order to try to protect the users and limiting the PHP/Perl from running out of their allowed space (i.e.: user/tmp folders). Its been a while ...
Have just assumed responsibility for a new client's site. OS is Linux. They had a cgi-bin directory below document root. I was looking at my error.log for an issue with a script and found a number ...