XSS/ BAD BEHAVIOR BLOCK
Blocks hacking attempts and automatically bans the hacker access to your website.
Recently It seems whenever I log into the oscommerce forums. I see a post stating their website has been hacked.
I packaged up what I use to stop XSS and other hack attempts.
It should work for most people.

No tough requirements.
You must have access to your .htaccess (the standard Apache/Linux web server)
It is a simple install. One new folder and one addition to your .htaccess file.

http://forums.oscommerce.com/topic/3...ehavior-block/

More...