Differentiate Between Virus, Trojan, Worm and Spyware. How do they harm to our computer?

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Question No:7

Matric no: 22755

Faculty: Resource Science and Technology

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Answer



Differentiate Between Virus, Trojan, Worm and Spyware. How do they
harm to our computer?

Virus:
A computer virus is a computer program that can copy itself and infect
a computer without permission or knowledge of the user. The original
may modify the copies or the copies may modify themselves, as occurs
in a metamorphic virus. A virus can only spread from one computer to
another when its host is taken to the uninfected computer, for
instance by a user sending it over a network or carrying it on a
removable medium such as a floppy disk, CD, USB drive or by the
Internet. Additionally, viruses can spread to other computers by
infecting files on a network file system or a file system that is
accessed by another computer. Viruses are sometimes confused with
computer worms and Trojan horses. A worm, however, can spread itself
to other computers without needing to be transferred as part of a
host. A Trojan horse is a file that appears harmless until executed.
In contrast to viruses, Trojan horses do not insert their code into
other computer files. Many personal computers are now connected to the
Internet and to local-area networks, facilitating their spread.
Today's viruses may also take advantage of network services such as
the World Wide Web, e-mail, and file sharing systems to spread,
blurring the line between viruses and worms. Furthermore, some sources
use an alternative terminology in which a virus is any form of self-
replicating malware.

Spyware:
Spyware is computer software that is installed surreptitiously on a
personal computer to intercept or take partial control over the user's
interaction with the computer, without the user's informed consent.

While the term spyware suggests software that secretly monitors the
user's behavior, the functions of spyware extend well beyond simple
monitoring. Spyware programs can collect various types of personal
information, but can also interfere with user control of the computer
in other ways, such as installing additional software, redirecting Web
browser activity, or diverting advertising revenue to a third party.

In response to the emergence of spyware, a small industry has sprung
up dealing in anti-spyware software. Running anti-spyware software has
become a widely recognized element of computer security best practices
for Microsoft Windows desktop computers. A number of jurisdictions
have passed anti-spyware laws, which usually target any software that
is surreptitiously installed to control a user's computer.

Trojan Horse:
Trojan horse is a program that installs malicious software while under
the guise of doing something else. A Trojan horse differs from a virus
in that a Trojan horse does not insert its code into other computer
files and appears harmless until executed. The term is derived from
the classical myth of the Trojan Horse. Trojan horses may appear to be
useful or interesting programs (or at the very least harmless) to an
unsuspecting user, but are actually harmful when executed. (See Social
engineering.)

Often the term is shortened to simply Trojan.

There are two common types of Trojan horses. One is ordinary software
that has been corrupted by a hacker. A hacker inserts malicious code
into the program that executes while the program is used. Examples
include various implementations of weather alerting programs, computer
clock setting software, and peer-to-peer file sharing utilities. The
other type of Trojan is a standalone program that masquerades as
something else, like a game or image file, in order to trick the user
into running the program.

Trojan horse programs cannot operate autonomously, in contrast to some
other types of malware, like viruses or worms. Just as the Greeks
needed the Trojans to bring the horse inside for their plan to work,
Trojan horse programs depend on actions by the intended victims. As
such, if Trojans replicate and distribute themselves, each new victim
must run the Trojan. Therefore their virulence is of a different
nature, depending on successful implementation of social engineering
concepts rather than flaws in a computer system's security design or
configuration.



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Is it important to install antivirus software? Why?



Yes.It is important to have antivirus software installed on your
computer to prevent infection by viruses, worms and spyware etc.
Viruses can spread via the Internet, chat facilities (such as MSN
Messenger), email attachments, infected files on CD's, USB sticks,
websites etc.



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