Short anti-spam and anti-virus information page


The word "spam" is used on the internet to refer to unsolicited email often promoting pornographic websites, get-rich-quick schemes, or goods you can buy.

For some it is a real nuisance, they are getting many of these emails a day, some get hardly any. Here are some tips on what you may be able to do about it:

Chain letters

These are related to spam, but they are sent out, sometimes by people who want to make a buck, sometimes as a joke. They then get sent on by people who obviously don't properly read the email and think about the content. Have you heard the story about the guy who invented chess? I'm not relating it correctly, but you'll get the idea. A king thought this was such a great invention that he offered the inventor anything he wanted that sounded reasonable. So the inventor asked for 1 grain of rice to be put on the first square of the chess board, twice that number on the second square, twice that number again on the third square. Doesn't sound like a lot, does it? Well, a chess board has 64 squares, on the last square the will be 9.22337E+18 grains of rice. The story goes on to tell that the inventor was beheaded by the king. Examples of chainletters that I have received were:

Viruses and Trojan Horses

This bit will primarily be relevant to users of Intel based PC's running Windows, and with one exception (that I'll get to) is the truth about these nasties. So how can they get inside your computer: Access is a very important word here. The mere presence of a nasty file on your harddisk, floppy, CD-ROM or in an email sent to you does not mean that you have to whip out that recent backup you have ready (you do have a backup, don't you?).

A trojan horse has to be available as executable code. In "the old days" that meant that only files with the extensions .EXE or .COM could be trojan horses or contain virusses. But now we also have things such as "Visual Basic Scripts" (.VBS) and Word or Excel macros. But whatever form they appear under, they have to exist as CODE, not just mere data.
And when YOU decide to run the code that contains the trojan horse or virus, you get bitten. Not before.

Lets look at a brief list of extensions used for different kinds of code:
COM Typically used by some MS-DOS programs
EXE Used by MS-DOS and Windows programs
VBS Visual Basic Script
JS JavaScript

So how do you run code?

Doubleclicking a program icon
Again, a program is a file with any of the above mentioned extensions. To be more "friendly" Windows usually hides the extensions of files on your harddisk. If you want to be able to see the extensions of files in Explorer (in Windows 98), choose "View -> Folder Options" and you will be presented with an option that says it all. Click on this link to see a screenshot of what it should look like.

Doubleclicking on an attached file within an email
When I doubleclick on an attached file sent to me by email, I see this. That is not yet dangerous. Saving it to disk is not dangereous. Selecting "Open it" and clicking OK is. If it is a virus, it may now be time to restore that backup of mine.