Last Tuesday we discussed two of the five types of viruses, the trojan horse, and the file infector.
Worms typically go after servers on the Internet.
They probe a server's weak points looking for holes. When they find one, they squeeze through and reproduce themselves until they fill up the server's memory, crashing the computer. Stealth viruses can sense when a virus checker is coming and hide themselves to avoid detection. The worst of the worst, though, is the polymorphic virus. Virus checkers work by searching for signatures, much like virus fingerprints.