Glossary
Trojan horse (trojan)
A booby-trapped program that hides inside normal-looking software and activates once you install it.
A Trojan horse passes itself off as useful software so that you install it yourself. Once in place, it acts in secret: opening an access point for the hacker, stealing data, installing other viruses. Unlike a classic virus, it does not spread on its own: it relies on trickery.
See also
Computer worm (worm)Malicious software that spreads on its own from one machine to another, without anyone having to click.SpywareSoftware that quietly watches your device to collect information without your knowledge.RootkitMalicious software that takes deep control of a machine while making itself invisible.Keylogger (keystroke logger)A snooping tool that records everything you type on the keyboard to steal passwords and messages.