[Book]

Hi,

If someone has a host file that is infected with a virus, then that does not mean that his computer is infected, since the virus has not necessarily run on his system. So what does it mean that a computer is infected by a virus? Does it mean that the virus is active in memory? But then again, what about non-resident viruses, which do not stay in memory?

A virus is a set of instructions, so if we say that a system is infected does that mean that it has executed those instrucitons at least once? But then again, in the case of non-resident viruses, deleting the host file(s) will solve the problem.

[ferrija1]

I would say infection is when you have a virus on your computer that has ran at least once, but I'm no expert.

[Book]

Still if the virus doesn't load itself into memory, it'll be like if you hadn't launched the virus in the first place!

[Book]

For example a HDD just containing an infected file wouldn't harm your computer. Copying, modifying the file wouldn't make any difference either.

The virus is not some grey cloud that will fog your computer once you execute it, since deleting the host files will eradicate the problem.

[lunarlander]

I think if you ask an antivirus company, they would say that if a virus exists on your hard drive, then there is an infection, and they would go about removing the virus. To them it wouldnt matter if the virus executed or not.

[mrss]

I agree with lunarlander. Your PC is infected if the file resides on the PC. Doesn't matter if it's in some folder where it might never get executed. What matters is that you or someone else did something to acquire that file and to me, that suggests the PC is compromised.

The few times I have encountered a virus, I bite the bullet, wipe the disks and re-install from a known good backup. I'd rather err on the side of caution. Anyway, it's very easy to do this with image software.

[Book]

Yes, but a virus *cannot* do anything that it's been written to do, unless its code is executed.

I'm asking this because often people treat an "infected" PC without actually knowing what causes that "infection". It's not that a virus will transform the PC in any different way that a normal program could. It's not like the infection is a state of the computer or some aura it gains because of the virus, the virus is just a program like any other (except for its purpose), and are bound by the same restrictions.

[ferrija1]

Originally Posted by Book

Yes, but a virus *cannot* do anything that it's been written to do, unless its code is executed.

I'm asking this because often people treat an "infected" PC without actually knowing what causes that "infection". It's not that a virus will transform the PC in any different way that a normal program could. It's not like the infection is a state of the computer or some aura it gains because of the virus, the virus is just a program like any other (except for its purpose), and are bound by the same restrictions.

I would even say that if a virus is waiting to execute, you're infected. There's no rock-solid definition, though.