Special Article:
HANDLING VIRUSES by Lance Jensen, Executive Software Tech Support
Director
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 e-mail with subjects such as "Good News!" or "AOL4FREE".
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 open a mail message and get a warning that the mail contains
macros, make sure you select the option to disable macros before you
continue.
2. If you 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.
Protection
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.
Or, since 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. But 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.
---------------------------------------------------------------------------- Lance Jensen is Executive Software
ace Tech Support Director, and has great experience with both Windows NT and Digital's
OpenVMS operating systems. He can be reached at dknt_support@executive.com.
Please feel free to write to him with questions or comments about this article.
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