A Computer Worm is a malicious program that targets whole computer networks instead of stand-alone computer systems. Unlike a computer virus, a worm can distribute itself by looking for other computers on a network so that it can spread to as many work-stations as possible.
Worms can do a lot of damage to both the network and the computers connected to it. A worm can dramatically decrease computer and network performance, increase network traffic and delete important system files. In some cases, the worm author can use a Backdoor with the worm to control the infected work-stations. Computers controlled by hackers as such are collectively known as “Zombie Computers”.
A group of Zombie Computers can be used to spread the worm to other computers and networks through email and instant messaging. When this happens, the network may be referred to as a “Botnet” (a group of computers within a network that communicate together to perform tasks), and the computers within may collectively be called “Bots”.
Computer Worms are also notorious for spreading by exploiting vulnerabilities in software, websites and operating systems.
An example of a computer worm, “MyDoom”, is currently the fastest spreading worm in history (As of 2004). The Worm is still viral today and comes in many variants!
Other notable worms, including the Morris worm, the CodeRed worm and the Conficker worm, have also caused damage on a monumental scale!
It’s fair to say that malware is a stronger force than you might expect…