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What’s a Computer Worm?

Rusaila Bazlamit on Flickr

In real life, worms may seem icky, but, unless you’ve experienced otherwise, they are not likely to attack you or steal your lunch money. In the computer world, worms are really nasty pieces of work. They like to infect computer systems and then make more copies of themselves to target more computers.

Computer worms especially love networks because they consist of lots of computers connected to one another. This gives the worms a convenient path through which they can spread to more and more computers.

A worm may sound like a computer virus, but there’s a difference. Viruses work by infecting a “host file” and “living” within it. If you’ve ever studied real-world human viruses, you’ll know that they like to hijack human cells for their own needs. In the same way, a computer virus hijacks a file to hide itself.

A worm, on the other hand, doesn’t hide. It’s a program that’s independent from any other file or folder and spreads itself as needed. Both viruses and worms are under the blanket term “malware,” which basically means “really nasty software that you never want to download.”

But wait a minute: why are they called worms? They don’t look like worms; they’re just a bunch of code. They’re not slithery, they’re not pink, and they don’t only come out when it rains…so where did this strange name come from?

The first ever computer worm to attack the internet happened back in 1988, with the Morris Worm. At the time, people needed a word to describe how the malware acted, and they found their answer in a novel published in 1975.

The Shockwave Rider tells the story of a dismal version of the 21st Century where technology has run amok. Given how this was written quite a while ago, some of the technology is actually outdated compared to what the 21st Century is actually like. However, the novel does predict one thing pretty well.

In the book, there are people who develop “computer tapeworms.” Tapeworms are special, because they can make more tapeworms by simply detaching segments from their bodies allowing a single tapeworm to make many more of itself and distribute these versions across a network. Sound familiar? While The Shockwave Rider’s tapeworms used a different method of duplication, it came very close to how today’s computer worms replicate themselves.

Learn More

Information on Tapeworms


Computer Worm on Wikipedia


The Shockwave Rider on Wikipedia


Computer Worms


What is a Computer Worm?


Morris Worm


Early Word Gets the Worm


List of Computer Worms


What is a Computer Worm


Difference Between Virus, Worm & Trojan Horse


Conficker Worm