Handling Viruses

We all know about computer viruses, and many people are quite worried about them, but they are not really dangerous if you understand them and take reasonable precautions.

E-Mail Viruses I'm sure you have all received e-mails warning you of dire consequences if you read an e-mail whose subject is "Good News!" or "AOL4FREE" or something like that. These are hoaxes intended to damage free communication by making people afraid to use e-mail. When you consider the time wasted reading and forwarding such things, they are as destructive as the real thing. It is not possible-NOT POSSIBLE-to get a virus by just reading an e-mail, unless the e-mail contains a macro or attachment that you then execute. Here are two simple rules that, if followed, will protect you from any e-mailed virus: 1. If you ever read a mail message and you get a warning that alerts you that the mail contains macros, make sure that you select the option to disable macros before you continue. (UNLESS you know that the file uses macros in order to operate correctly... when in doubt disable the macros. You can always open it again with macros enabled if it becomes obvious that the macros are needed. Note that probably 90% or more files do not have any necessary macros in them) 2. If you ever receive a mail message from someone you do not know and that mail contains an attachment, do not open the attachment till you have made sure the attachment does not contain a virus. There are programs on the market that can be used to check such things.

You should also be aware that both Microsoft Excel and Microsoft Word have a built-in macro checker that will alert you to the existence of a macro in a file that you open as long as you do not disable this function. The next time you get one of these hoaxes, instead of forwarding it, please reply to it with this article.

Sources of Viruses

Computer viruses are not as common as most people believe, and rather easy to avoid. Commercial software on commercial CD-ROMs is almost guaranteed to be virus-free, but any software on floppy disks or non-commercial CDs can be a risk. Anyone can make floppies and non-commercial CDs, and can put anything they want on them. It doesn't matter who wrote the program; someone else can add to it or alter it. Commercial CDs have data, usually the name of the company that burns the CDs, burned into the inside track and visible to the naked eye. Recordable CDs lack this, and usually have a batch number on the unsilvered area of the hub. Be wary of any CD that lacks this identification, and certainly of anything with a stick-on label. Of course, even a commercial CD could be infected, since a criminal could hack into the manufacturer's system and plant a virus before the CD master is made, but this is extremely unlikely.

By far the most common source of a virus infection is downloaded software. Anything downloaded can be infected, even from big, reliable, long-established companies. It's not easy for criminals to break into such systems, and it certainly is very rare, but it has been done. A public bulletin board (BBS) is probably the easiest place to plant a virus. A good Sysop (the System Operator for the BBS) can keep the BBS clean, but some are careless.

Some viruses attach themselves to programs on the infected system, and are transmitted to other systems when the programs are copied. If a friend gives you a copy of a program, check it for a virus, even if you trust your friend; his system may be infected.


It is a good idea to have an anti-virus program; they are cheap, easy to use, and easy to keep updated. You do have to keep getting the updates, because these programs use an anti-virus database to recognize viruses, and this database must be upgraded when new viruses are discovered. Sometimes an anti-virus program will interfere with the installation of new software, especially if you are installing a Service Pack. That means you should disable the anti-virus when installing new software, but that leaves you unprotected should there be a virus. What now?

The best defense is to have a test machine, not on a network, not connected to anything else. You disable the anti-virus on the test machine, load the new software, then start the anti-virus and test. Once you have established that the software is clean, you can load it onto your production system. OK, most of us can't afford to have a machine we only use for virus checking. The next best solution is a test disk. On my home machine, Disk 0 is a 2GB IDE disk, with two 1GB partitions. The first is a secondary Windows NT installation which I use to repair my primary system partition as needed. The other partition has Windows NT installed, but the disk configuration only sees the two partitions on Drive 0. I boot to it and do virus checks. I figure the worst a virus can do is wipe out the two partitions on Disk 0, and they are easily rebuilt.

Naturally no system or procedure can guarantee absolute safety. If you are reasonably careful, use an anti-virus, always virus-check new software, and keep your backups updated, you should never have any significant trouble from a virus. For more data on virus hoaxes, try these sites: http://kumite.com/myths/home.htmLance Jensen Technical Support Manager Executive Software* International, Inc.