security attack

http://www.boonex.com/unity/forums/topic/Troubleshooting-Possible-Security-Attacks-.htm

I assume you're running an older version. PHPIDS was disabled by default in more recent versions, because of the problems it caused.

Edit: I should add that in that topic, the information may be a bit outdated, since security-related settings now have their own section under Administration > Settings > Advanced Settings > Security.