Have you ever receiver link from your faceboot friend chat lik "Hi...click this link, there was a sexy picture", that link provide by free file sharing sendspace. Picture like below
If you receive link from your facebook friend chat, dont click that, because that will infected your computer by virus Graftor a.k.a IRCbot.CMBJ.
If do you use antivirus from G-Data, you will receive a notification that your pc infected by “Virus:Gen:Variant.Graftor.41286”, and that link (from sendspace file share) will block at the browser.
How if you have infected but you dont have update antivirus yet? You can download removal tool from norman antivirus, that link IRCbot.CMBJ removal tool
Source: http://www.vaksin.com/2012/0912/facebot/facebot.html