The Koobface worm was first identified back in August of 2008 and is still in circulation to this day.
As you may be able to tell from the name (its an anagram of Facebook) the worm has been designed to target social networking sites.
Koobface spreads itself by sending intriguing messages to Facebook friends with subject headers that are designed to encourage clicks, such as “You look just awesome in this movie”.
If the person who receives the message clicks on the included link then they will be directed to a page where they can play the ‘video’.
Before watching, however, they will be told that they need to install the latest version of Flash in order to watch the clip.
Of course the link to the supposed Flash player is fake and instead contains the virus which will then take the user to infected sites across the web.
Read more : Malware That Changed The World