Koobface is a real piece of malware that began circulating in late 2008 via messages sent through social networking sites such as Facebook and MySpace. However, since mid-2010 warnings about Koobface circulated online have mutated into a versions which are largely hoaxes:
Virus spreading like wildfire on FaceBook!! It is a trojan worm called "koob face". It will steal your info, invade your system and shut it down! Do NOT open the link "Barack Obama Clinton Scandal"! If "SmartGirl15" adds you, don't accept it; it is a virus. If somebody on your list adds her then you get the virus too!! Copy and paste to your wall.
Koobface is not "spreading like wildfire" on Facebook (social networking increased their protection in the wake of such malware outbreaks, so Koobface largely stopped using them as a means of transmission), there is no evidence that Koobface was ever widely spread via "Barack Obama Clinton Scandal" messages, and the warning about "SmartGirl15" was just another updating of another long-running Internet hoax.
Back in 2008, the Koobface
Facebook sent the following instructions to users whose accounts may have been compromised:
We have detected suspicious activity on your Facebook account and have reset your password as a security precaution. It is possible that malicious software was downloaded to your computer or that your password was stolen by a phishing website designed to look like Facebook. Please carefully follow the steps provided:
Run Anti-Virus Software: If your computer has been infected with a virus or with malware, you will need to run anti-virus software to remove these harmful programs and keep your information secure. For Microsoft: