# What's the difference between a worm and a virus

**URL:** <https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978>\
**Category:** Factual Questions\
**Created:** [August 22, 2003, 6:01pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978 "2003-08-22T18:01:42Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\
**Post date:** [August 22, 2003, 6:01pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978/1 "2003-08-22T18:01:42Z")

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What is the technical difference between a worm and a virus?

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**Author:** ![Capt.Ridley\_s\_Shooting\_Party](https://avatars.discourse-cdn.com/v4/letter/c/cc9497/32.png) [@Capt.Ridley\_s\_Shooting\_Party](https://boards.straightdope.com/u/Capt.Ridley_s_Shooting_Party)\
**Post date:** [August 22, 2003, 6:08pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978/2 "2003-08-22T18:08:18Z")

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As I understand it, a worm actively seeks out new victims (or attempts to send itself to new victims) once it has infected a host. A virus won’t do this, if my understanding is correct.

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**Author:** ![godzillatemple](https://avatars.discourse-cdn.com/v4/letter/g/49beb7/32.png) [@godzillatemple](https://boards.straightdope.com/u/godzillatemple)\
**Post date:** [August 22, 2003, 6:20pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978/3 "2003-08-22T18:20:04Z")

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Actually, a virus replicates itself by inserting itself into other programs, so that when that program is opened the infection spreads.

A worm, on the other hand, is a self-contained program. Once executed, it replicates by sending out copies of itself, but it does not insert itself into other code.

Barry

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**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\
**Post date:** [August 22, 2003, 6:22pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978/4 "2003-08-22T18:22:06Z")

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[McAfee Virus Glossary](http://us.mcafee.com/virusInfo/default.asp?id=glossary)

> [@](#):
>
> **Worms are parasitic computer programs that replicate, but unlike viruses, do not infect other computer program files. Worms can create copies on the same computer, or can send the copies to other computers via a network. Worms often spread via IRC (Internet Relay Chat).**

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**Author:** ![Daizy](https://avatars.discourse-cdn.com/v4/letter/d/46a35a/32.png) [@Daizy](https://boards.straightdope.com/u/Daizy)\
**Post date:** [August 22, 2003, 6:25pm UTC](https://boards.straightdope.com/t/whats-the-difference-between-a-worm-and-a-virus/196978/5 "2003-08-22T18:25:34Z")

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[Symantec’s description of the difference between a worm, virus and trojan.](http://service1.symantec.com/SUPPORT/nav.nsf/docid/1999041209131106?Open&src=&docid=2002062515414606&nsf=nav.nsf&view=3353489cd5cd08c388256c0e005a96e4&dtype=&prod=&ver=&osv=&osv_lvl=)