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Help in defining the meaning of a Virus & Worm

Help in defining the meaning of a Virus & Worm

Help in defining the meaning of a Virus & Worm

Hi there,

I've been reading up on Virus's and Worms for a short presentation and I'm having just a little trouble when it comes to really defining the difference between the two because there seems to be some cross-over and very close similarities.

I have read that the difference is that a virus self-propagates and a worm self-replicates but if that is the difference, what's the difference between self-propagating and self-replicating because both seem to have the same meaning and that is that they both copy themselves.

If they both do that same primary function (copy themselves), are they then defined more on what they do in addition to this?

Thanks for any advice

RE: Help in defining the meaning of a Virus & Worm

Okay the definitions are confused a bit because of how people throw around terms, but here is the difference:

A computer virus requires host executables in order to spread itself.  This is how a virus resides on a computer.

A computer worm, however requires no host executable and in fact a whole executable file is this worm.

In biology think of the difference between a virus and a bacteria.  That should help.  If you want to know more, the wikipedia pages are sufficient in delineating the definitions of the two.

It is not possible for anyone to acknowledge truth when their salary depends on them not doing it.

RE: Help in defining the meaning of a Virus & Worm

Thats not how I would define it Glenn.

I would say...

A Virus can be an executable, and is a generic term for any malicious code running on a computer system.

A worm is a special type of virus that is designed specifically to infect a system then send copies of itself to other systems( usually via the Internet).

Steve: N.M.N.F.
If something is popular, it must be wrong: Mark Twain

RE: Help in defining the meaning of a Virus & Worm

Since you are doing research on the subject, there was a paper published not too long ago, discussing the "Folk Wisdom" used to make computer security decisions.  I can't recall the exact title, but I think Bruce Schneier's website might have a link to it.  One of the key topics of the paper was the "common" perception of what a virus is and how far from accurate it is.

RE: Help in defining the meaning of a Virus & Worm

Thanks for the input!

I've continued with my research and found some info on


that says:

A computer virus is a small program written to alter the way a computer operates, without the permission or knowledge of the user. A virus must meet two criteria:
1. It must execute itself. It often places its own code in the path of execution of another program.

2. It must replicate itself. For example, it may replace other executable files with a copy of the virus infected file. Viruses can infect desktop computers and network servers alike.

This about Worms:

Worms are programs that replicate themselves from system to system without the use of a host file. This is in contrast to viruses, which requires the spreading of an infected host file. Although worms generally exist inside of other files, often Word or Excel documents, there is a difference between how worms and viruses use the host file. Usually the worm will release a document that already has the "worm" macro inside the document. The entire document will travel from computer to computer, so the entire document should be considered the worm W32.Mydoom.AX@mm is an example of a worm.

In my search to find the answer it does seem a bit like, it all depends on who you ask so I'm going to go with the info that is on a trusted (I hope!) site...Glenn your answer is spot on, thanks.

I haven't found the article you mentioned Noway but thanks for pointing out that site! very useful.

Thanks all  

RE: Help in defining the meaning of a Virus & Worm

Found it.  Here is a link: http://www.schneier.com/blog/archives/2011/03/folk_models_in.html

The primary focus of the article was on modeling and classifying different groups of users and then based upon the group analyzing the security decisions that they made.  One of the aspects considered was "what they thought a virus was."  For example, in one of the group classifications, viruses were commonly thought of as programs planted by "hackers" to cause mischief.  It has been quite a while since I read to remember all the details, but I thought it might provide some interesting insights for your research.

RE: Help in defining the meaning of a Virus & Worm

Thanks Noway looks like a good read!

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