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| Viruses,
worms, trojans and bakdoors |
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Other harmful 'relatives' of viruses.
Along with viruses,
there are three other types of damaging programs which
are the bane of all computer users worldwide: Trojans,
worms and backdoor. Although they have similar effects
to viruses, these programs have clearly distinguishing
characteristics.
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Virus |
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A virus is a program
that can enter a computer in many different ways and can
cause effects ranging from the simply annoying to the
highly destructive. Viruses can enter computers through
e-mail, the Internet, different types of disks etc, and
they have the following characteristics:
- They have the ability to reproduce infecting
other files and programs.
- When they are run, they are able to carry out a
range of annoying or damaging actions in your
computer.
Computer viruses are called viruses due to their similarities
with biological viruses.
In the same way that biological viruses enter the body
and infect cells, computer viruses get into computers
and infect files. Both types of virus can reproduce
themselves and spread, passing the infection from one
infected system to another. Also, just as a biological
virus is a micro-organism, computer viruses are micro-programs.
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Worms |
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A worm is a program very similar to a virus. It has the ability to self-replicate,
and can lead to negative effects on your system. However,
worms do not need to infect other files in order
to reproduce.
Worms, unlike viruses, simply replicate themselves
without damaging files, but can reproduce rapidly, saturating a network and causing it to collapse.
Normally sent via e-mail, some of the most
notorious include: I
Love You, Navidad,
Pretty
Park, Happy99
and ExploreZip.
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Trojans |
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Another unsavory breed of virus are Trojans or Trojan horses,
which unlike viruses do not reproduce by infecting other files nor do they self-replicate like worms.
Trojans work in a similar way to their mythological namesake,
the famous wooden horse in which Greek soldiers hid so that they could enter the city of Troy undetected.
They appear to be harmless programs that enter a computer through any channel.
When that program is run (they have names or characteristics which trick the user into doing so),
they install other programs on the computer that can be harmful.
A Trojan may not activate immediately, but when it does, it can wreak
havoc on your system. They have the capacity to delete
files, destroy information on your hard drive and
open up a backdoor to your security system. This gives
them complete access to your system, allowing an outside
user to copy and resend confidential information.
Some examples of Trojans are Backdoor,
Donald Dick, Crack2000,
Extacis, KillCMOS
and Netbus.
For more information, go to
Types of Viruses.
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Backdoor |
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A backdoor is a program that can get into computers
without user realizing, passing itself off as a harmless
program. Once it has been run, it opens a backdoor
through which it can control the affected computer.
This allows a malicious user to carry out actions on the
affected computer that can compromise user confidentiality
or impede the operations carried out.
The actions that backdoor allow malicious users
to carry out can be extremely damaging. They could
allow them to delete files or destroy all the information
on the hard disk, capture confidential data and send
it out to an external address or open communications
ports, allowing remote control of the computer.
Some examples of backdoor are: Orifice2K.sfx,
Bionet.318,
Antilam
and Subseven.213.
For more information, go to Types
of Viruses.
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