Facebook is a great place to meet your friends, to have fun or to take part in discussions - and to get infected with a Facebook Trojan virus and other Facebook malware. Facebook viruses and other Facebook malware are abundant and many of them are high-risk. The Koobface worm is probably the best known Facebook malware but compared to Facebook Trojan viruses, this worm is sweet and harmless.
Facebook viruses use many algorithms to infect you and even if you are a security pro, you can never be sure you know all the ways in which you can be infected by a Trojan virus. However, if you don't take even the simplest measures to protect yourself against Facebook viruses, then it is almost guaranteed that sooner or later you will pick one up.
For instance, one of the most common ways to get infected is if you click on a video that has the virus attached. Facebook is about exchanging videos, so probably you click many videos each time you visit. It's not realistic to expect that you will never watch a video on Facebook and there is always a risk, but if your antivirus program is always up-to-date, chances are it will catch the Facebook virus before you get infected.
In addition to videos, applications are another risky Facebook feature. This is why you should always be careful when you use applications on Facebook. Use only trusted applications and as with videos, keep your antivirus program updated at all times. Firewalls don't help, so if you thought that your firewall will protect you, it probably won't.
Videos and applications are risky but any link, especially to an external site you see anywhere on Facebook, is another potential hiding place for Trojan viruses on Facebook. Downloads are also risky, so don't download things from Facebook. Fortunately, Facebook doesn't offer upload functionality, so no .exe files and similar stuff can be distributed. Still, there are things you might be tempted to download, most notably pictures and videos – just don't do it.