What is a Virus?
A computer virus is a program - a piece of executable code -
that has the unique ability to replicate. Like biological
viruses, computer viruses can spread quickly and are often
difficult to eradicate. They can attach themselves to just
about any type of file and are spread as files that are
copied and sent from individual to individual.
When you listen to the news, you hear about many different
forms of electronic infection. The most common are:
Viruses - A virus is a small piece of software
that piggybacks on real programs. For example, a virus
might attach itself to a program such as a spreadsheet
program. Each time the spreadsheet program runs, the virus
runs, too, and it has the chance to reproduce (by
attaching to other programs) or wreak havoc. E-mail viruses - An e-mail virus moves around
in
e-mail messages, and usually replicates itself by
automatically mailing itself to dozens of people in the
victim's e-mail address book. Worms - A worm is a small piece of software
that uses
computer networks and security holes to replicate
itself. A copy of the worm scans the network for another
machine that has a specific security hole. It copies
itself to the new machine using the security hole, and
then starts replicating from there, as well. Trojan horses - A Trojan horse is simply a
computer program. The program claims to do one thing (it
may claim to be a game) but instead does damage when you
run it (it may erase your
hard disk). Trojan horses have no way to replicate
automatically.
Viruses won't go away anytime soon: More than 60,000 have
been identified, and 400 new ones are created every month,
according to the International Computer Security Association
(ICSA). With numbers like this, it's safe to say that most
organizations will regularly encounter virus outbreaks. No
one who uses computers is immune to viruses.
Antivirus
Everyone who uses a computer has been at one time or another
indebted to antivirus software. It sits like a watchdog in
your PC's backyard, waiting for some pesky virus to jimmy
the lock and try to mess with the treasures you've stored in
the inner sanctum of your hard drive. And, like a
high-strung Doberman, an antivirus is much more useful to
you if you understand how it operates, when to feed it, how
often to walk it, et cetera. |
