What is a virus

Are there rules that decide if a given program is a virus?

If I maka a simple program that creates a txt file somewhere in system directory (ex. WINDOWS\system32) and via a infinite loop writes text to the file eventualy filling up a hard drive, is that program a virus ?

Originally Posted by Suchy

Are there rules that decide if a given program is a virus?

If I maka a simple program that creates a txt file somewhere in system directory (ex. WINDOWS\system32) and via a infinite loop writes text to the file eventualy filling up a hard drive, is that program a virus ?

No. A virus is a program which embeds itself in another program, and uses the execution of the infected program as a means of spreading itself. The program you are describing is a plain old denial-of-service attack.

My definition is any type of program whose intent is malicious and therefore contains malicious code.
Anyway, here's wikipedia's take on it: http://en.wikipedia.org/wiki/Computer_virus

Originally Posted by Suchy

Are there rules that decide if a given program is a virus?

If I maka a simple program that creates a txt file somewhere in system directory (ex. WINDOWS\system32) and via a infinite loop writes text to the file eventualy filling up a hard drive, is that program a virus ?

I think malware is here the genius. For a definition of the words malware and virus propose using wikipedia.

If it's a pain in the ass it's a virus, and you suck for writing it.

EDIT:
Oh yeah, 'in my humble opinion.'

Originally Posted by BobMcGee123

If it's a pain in the ass it's a virus, and you suck for writing it.

Is that why all of my wonderful coworkers complain to me that their computer is infected with a virus when their computer locks up after they incorrectly enter their password three times in a row?

What kind program/os locks up because you misspelled your password 3 times?? (or is that actually a safety?)

Computer Virus: Elysia.
Now you know what happened to the board!

Originally Posted by Suchy

Are there rules that decide if a given program is a virus?

As brewbuck said.
You may also want to check on these names: trojan horse, computer worm, malware, and even spyware.

Unfortunately, like with many other things these days, proper usage of these terms is being deterred by the Pop Culture For The Masses perpetrated by the media at large; my term, so take it as you want. It just means this horrendous idea that people are ignorant and incapable of learning and as such its easier if you just cut down on the lingo and adopt the catch phrases instead.

The press loves it and is the main responsible for the confusion on this and many other issues - "hackers" being another one that is today totally devoid of its true meaning. The world of computing was a much more accurate place before it become news. Some of the things I hear on prime time news... sorry, need to check my blood pressure.

Anyways, ranting aside, check those terms on wikipedia, for starters, if you want to have a more accurate description of their meanings.

Is that why all of my wonderful coworkers complain to me that their computer is infected with a virus when their computer locks up after they incorrectly enter their password three times in a row?

I believe the response that you want is 'no comment.'

Originally Posted by Yarin

What kind program/os locks up because you misspelled your password 3 times?? (or is that actually a safety?)

You'd be surprised how many things actually lock themselves today when you type wrong password 3 times!

Any software written with ill intentions is a Virus!
Now how it does that is a moot point!

Not always. That's why we have a malware category!

Brewbuck's definition of a computer virus is correct; as in it behaves like a biological virus. The word is often used to describe malware in general, but this is misleading. For example a lot of anti-virus software wont protect you from all malware such as rootkits or spyware, which seem to be more a threat than viruses nowadays.

I thought a virus was self-replicating, and a worm was replicated in a host program. Or is it the other way around?

I think you have those two mixed up.
Virus infects other programs to do its work.