OK, now you know what these little buggers are and how they work. Now, how do you avoid them? Well, read on for tips on avoiding all sorts of different types. We'll start with E-mail viruses since they're the most common.

What Kind of Attachments Can Contain Viruses?

Basically, anything that is executable (able to run). You're generally safe with picture files, text files, and the like. However, it still pays to scan first.

Here is a (very) short list of the most common to watch out for:

exe
zip
scr
vbs
bat
com
pif
asp
doc
xls

Those are the most common. Please, please, I beg you, don't misinterpret this to mean that if you get one of these files it's automatically a virus. A ".zip" file may be nothing more than a set of compressed files your friend sent you to look at. A "doc" or "xls" file may simply be an MS Office file. It's just that these type of files could also be viruses.

A couple other virus tricks you need to be aware of. First, MS Office files can contain what are called "Macro Viruses". Without getting into too much detail, these files can run a "macro" (a macro is a mini-program run from within another program) that can be as destructive as any "regular" virus. So, my advice on MS Office attachments is not to open them unless you are expecting them. If they just show up, verify with the sender first.

The other trick you need to look out for is an extra extension added to an attached file. For example, you may have something like "mypicture.jpg.vbs". In fact, if you don't have your computer set to view file extensions, it may just look like "mypicture.jpg" and omit that last "vbs" part.

This may appear to be a jpg picture file, but it's actually a Visual Basic Script file. If executed, it will happily infect your computer with a virus.

So, be careful out there.

Avoiding E-mail Viruses

Most e-mail viruses only exist to replicate themselves, kind of like a digital bacteria. Others may do damage to your computer's files or even make your hard drive inaccessible.

What can you do?

Don't open attachments if you're not expecting them - EVER. If you get an attachment, e-mail whoever it was that sent it to you to confirm it's not a virus. Checking it with your anti-virus software isn't a bad idea either. Next to good anti-virus software, this is the #1 way to keep your computer virus free.

If you don't have any anti-virus software, get some. And keep it up to date.

If you have anti-virus software that's up to date, don't rely on it to stop every virus. New viruses (10-15) are created each and every day. No one had a defense when the ILOVEYOU virus first hit, but folks who didn't run the attachment got away unscathed. (Although Norton AV seems to have updates available within hours of a new virus discovery)

Finally, there is a slim chance that you may run across a virus that can infect your computer without it being run.

These viruses take advantage of a security holes in some e-mail clients, namely Outlook / Outlook Express (they can also infect you if it's on a web page viewed with MS Internet Explorer). These holes have been sealed through a patch you can get from Microsoft.

The lesson? Keep both Internet Explorer and Outlook / Outlook Express up to date. Updates are free, so there's no good reason not to keep your software current.

Remember, 99.99% of the viruses out there must be run by YOU in order to infect your computer. If you get a virus e-mailed to you, you're generally safe reading the body of the e-mail message, JUST DON'T RUN THE ATTACHMENT!! A virus can't infect your computer until you give it your consent (well, unless someone hacks into your machine and runs it, but that's another newsletter).

If you do get a file that you suspect contains a virus, just delete it.

Don't open attachments if you're not expecting them - EVER. If you get an attachment, e-mail whoever it was that sent it to you to confirm it's not a virus. Checking it with your anti-virus software isn't a bad idea either.

Next, some other ways to pick up a virus.

Posted in: Part - 2