Email brought them into fashion in the late 1990s, and for nearly a decade, computer security pros were besieged by malicious worms that arrived as message attachments.

Worms have been around even longer than computer viruses, all the way back to mainframe days. The best antivirus programs struggle with doing it correctly and in many (if not most) cases will simply quarantine or delete the infected file instead. This has always been nontrivial, and today it's almost impossible. That makes them particularly hard to clean up because the malware must be executed from the legitimate program. That's a good thing: Viruses are the only type of malware that 'infects' other files. Pure computer viruses are uncommon today, comprising less than 10% of all malware. A computer virus modifies other legitimate host files (or pointers to them) in such a way that when a victim's file is executed, the virus is also executed. Fortunately, most malware programs aren't viruses. VirusesĪ computer virus is what most of the media and regular end-users call every malware program reported in the news.

This concise malware bestiary will help you get your malware terms right when you hang out with geeks. However, it's important to get your malware classifications straight because knowing how various types of malware spread is vital to containing and removing them. People tend to play fast and loose with security terminology.

Trojan maker take over computer