New Variant of Koobface Worm on Facebook
It appears that a newer variant of the Koobface worm is making the rounds on Facebook and other social networking sites like MySpace and Friendster. Here is a description of how this worm works within Facebook:
You will receive a message in your Inbox from one of your Friends. This message will invite you to take a look at a video, and contain a link to an external web site, pretending to be YouTube, from which to view this video. Once on the new web site, you will be instructed to install an Adobe Flash plug-in in order to view the video. Clicking on the link to install the Adobe plug-in will take you to a malicious web site which will actually install the worm on your computer.
If you download the worm, the worm will spread its way across your friends on the social network web site, and may also gain access to personal information on your computer. Depending on the exact variant of the worm, it is possible the worm is able to extract information like credit card information, sniff out keystrokes and therefore gain password access information, and perform all kinds of other spam and malicious activities.
Our advice is to never follow links that appear suspicious. We also encourage you to never install anything from a web site which is not a trusted site. In the above example, if you needed to install an Adobe plug-in for any reason you should go to the Adobe.com web site directly, and locate the download from their site. Do not trust third party sites that provide similar looking downloads, as it is very possible that they have been tampered with.