PerlIDS (CGI::IDS) is a Perl website intrusion detection system based on PHPIDS http://php-ids.org/. It parses any hashref for possible attacks, so it does not depend on CGI.pm.
The intrusion detection is based on a set of converters that convert the request according to common techniques that are used to hide attacks. These converted strings are checked for attacks by running a filter set of currently 68 regular expressions. For easily keeping the filter set up-to-date, PerlIDS is compatible to the original XML filter set of PHPIDS, which is frequently updated.