The Security Mentor

Your antivirus software works two different ways. It checks things against a list of known viruses, like a police officer scanning people's faces against the wanted list. It also looks for suspicious behavior, like a police officer stopping someone who is acting strangely.

Lots of new viruses come out every day. That's why it's so important to keep up with the automatic updates for your antivirus software. That also tells you that there are always viruses that are too new for your antivirus software to know about, so it's really important that it be able to recognize virus-like behavior.

Unfortunately today's crop of viruses is pretty good at evading suspicion. A recent German study of antivirus software found that most antivirus products could detect only 20-30% of viruses not already on their watch lists. Even the most successful one, NOD32 from eSet, only caught 68%.

Your best defense is to be careful what you download.

English article about the German study