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A computer virus must piggyback on top
of some other program or document in order to get
executed. Once it is running, it is then able to infect
other programs or documents. Obviously, the analogy
between computer and biological viruses stretches things
a bit, but there are enough similarities that the name
sticks.
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.
- 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.
- 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.
We'll take a closer look at how a worm works in the
next section.
- Adware
-
While not necessarily malware, adware
is considered to go beyond the reasonable advertising
that one might expect from freeware or shareware.
Typically a separate program that is installed at the
same time as a shareware or similar program, adware
will usually continue to generate advertising even
when the user is not running the originally desired
program.
- Malware -
“Malicious software”; a generic term
covering a range of software programs and types of
programs designed to attack, degrade or prevent the
intended use of an ICT or network. Types of malware
can include viruses, worms, Trojans, malicious active
content and denial of service attacks. In the case of
invasion of privacy for the purposes of fraud or the
theft of identity, software that passively observes
the use of a computer is also malware (“spyware”).
- Spyware -
Any software that covertly gathers
user information through the user's Internet
connection without his or her knowledge, usually for
advertising purposes. Spyware applications are
typically bundled as a hidden component of freeware or
shareware programs that can be downloaded from the
Internet. Once installed, the spyware monitors user
activity on the Internet and transmits that
information in the background to someone else. ...
- Spam -
To indiscriminately send unsolicited,
unwanted, irrelevant, or inappropriate messages,
especially commercial advertising in mass quantities.
Noun: electronic "junk mail". While spam is not
necessarily an electronic infection, it is a carrier
or the form used to spread many electronic infections.
Where do Viruses come from?
People create viruses. A person has to
write the code, test it to make sure it spreads properly
and then release the virus. A person also designs the
virus's attack, whether it's a silly message or
destruction of a hard disk. So why do people do it?
There are at least three reasons. The
first is the same psychology that drives vandals and
arsonists. Why would someone want to bust the window on
someone else's car, or spray-paint signs on buildings or
burn down a beautiful forest? For some people, that
seems to be a thrill. If that sort of person happens to
know computer programming, then he or she may funnel
energy into the creation of destructive viruses.
The second reason has to do with the
thrill of watching things blow up. Many people have a
fascination with things like explosions and car wrecks.
When you were growing up, there was probably a kid in
your
 neighborhood
who learned how to make gunpowder and then built bigger
and bigger bombs until he either got bored or did some
serious damage to himself. Creating a virus that spreads
quickly is a little like that -- it creates a bomb
inside a computer, and the more computers that get
infected the more "fun" the explosion.
The third reason probably involves
bragging rights, or the thrill of doing it. Sort of like
Mount Everest. The mountain is there, so someone is
compelled to climb it. If you are a certain type of
programmer and you see a security hole that could be
exploited, you might simply be compelled to exploit the
hole yourself before someone else beats you to it.
"Sure, I could TELL someone about the hole. But wouldn't
it be better to SHOW them the hole???" That sort of
logic leads to many viruses.
Of course, most virus creators seem to
miss the point that they cause real damage to real
people with their creations. Destroying everything on a
person's hard disk is real damage. Forcing the people
inside a large company to waste thousands of hours
cleaning up after a virus is real damage. Even a silly
message is real damage because a person then has to
waste time getting rid of it. For this reason, the legal
system is getting much harsher in punishing the people
who create viruses.
How do you protect your computer
from viruses?
You can protect yourself against
viruses with a few simple steps:
1) Buying virus protection software is
a nice safeguard. We recommend AVG Anti-Virus software,
however there are several on the market. Once you buy it
you need to install it & keep it updated, if you don't
keep up with the updates it won't protect your computer.
2) Avoid programs from unknown sources
(like the Internet), and instead stick with commercial
software purchased on CDs, you eliminate almost all of
the risk from traditional viruses.
3) Make sure that Macro Virus
Protection is enabled in all Microsoft applications, and
you should NEVER run macros in a document unless you
know what they do.
4) Never double-click on an e-mail
attachment that contains an executable. Attachments that
come in as Word files (.DOC), spreadsheets (.XLS),
images (.GIF and .JPG), etc., are data files and they
can do no damage (noting the macro virus problem in Word
and Excel documents mentioned above). A file with an
extension like EXE, COM or VBS is an executable, and an
executable can do any sort of damage it wants. Once you
run it, you have given it permission to do anything on
your machine. The only defense is to never run
executables that arrive via e-mail.
By following those simple steps, you
can remain virus free. |
