PHPIDS is a well known project that can be found in [php-ids.org](http://php-ids.org "php-ids.org"). PHPIDS is an intrusion detection system, essentially based on IDS rules, it recognizes attacks by filtering information sent to the
system and returns a rating and a report of what is
considered a potential attack. From this information the system
can react to the attack, send e-mail alerts, generate detailed logs,
block the user, generate black list, etc..