Define malware and distinguish among a virus, a worm, and a trojan horse.

Malware is software that is used to gain unauthorized access to someone's computer or to disrupt and damage their system.

A worm is a corrupted program or file that copies itself repeatedly onto the victim's computer in order to use up memory and disk space and eventually crash their computer.

A virus is a deliberately written program which activates itself unknown to the user and destroys and disrupts data.

a Trojan horse is a type of virus that places destructive code in programs such as games. When the user runs the game, the hidden code secretly runs in the back ground and either erases their entire hard disk or some programs on the hard disk.