Reports have been circulating about a virulent worm spreading through Facebook. The virus has been around since August but now targets social networking websites only and is currently making the rounds on Facebook.

The virus can spread fast because they travel through messages which appear to come from your friends.

The Koobface messages carry subject lines like “You look so funny on our new video” or something similar, and contain a link to a video site that appears to contain a movie clip. If the user tries to watch it, a message appears saying that he or she needs the latest version of Flash Player in order to play the clip. This tricks users into downloading a file carrying the malware.

Facebook says that users should use antivirus software and change their password if they’ve been affected. The company also appears to be resetting passwords pro-actively and notifying users per e-mail about the possibility of having a virus on board.