StopSign

Summary:
Disables security software. Purports to be security software.

Category:
Adware - displays numerous popups recommending purchase of various Acceleration Software products. Firewall Killer - interferes with operation of several personal firewalls. Loader - quietly installs other files. Exploit - uses social engineering and stealth tricklers to gain control of the system.

See full article here (and thanks to PestPatrol for the info):

http://www.pestpatrol.com/PestInfo/S/StopSign.asp#TOP