http://www.digitaljournal.com/article/268646

Facebook Worm 'Koobface' Resurfaces

Posted Mar 6, 2009 by Bob Ewing
A worm that takes over computers by spreading through Facebook has morphed, it now poses as YouTube video, and returned to infect Facebook users.
koobface
TrendMicro
koobface
The Facebook worm works just like its predecessor did but has been tweaked and now has an updated look and code that might not be caught as quickly.
Koobface tricks the user into following a link.
The difference between the new version and the older one is the page with the video is professional-looking YouTube spoof, complete with the impression that the video has been posted by your Facebook friend.
If you install the malware it will steal your logon credential from Facebook and other sites and send the message on to your friends on those social networking sites.