Difference Between Virus, Worm and Trojan Horse

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Difference Between
Virus,
Worm
and
Trojan
Horse
Often people mix terms like worms, trojan,
spyware, they use them whenever there is a
discussion on computer virus. But let me tell you
using them interchangeably is not correct. These
terms cannot be used when we talk about virus
they all are different. Viruses, worms and
trojan horses are malicious programs, they cause
damage to your computer, but the way they harm a
system is what makes them stand apart.
To protect our system from these threats we need
to understand the terms and their difference. In
this article, we will help you understand them
better.
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Threats Computer virus attaches itself to a
program or file, as these application and files
travels from one system to another infection
spreads. Computer viruses are dangerous but they
vary in severity Some make the system slow and
sluggish while others cause damage to the
hardware, software and files stored on the system
thus making system in-operational.
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As viruses are attached to an executable file
they cannot function without human intervention.
They can sit into the system but wont work until
the malicious file or application is opened or
run. Users play an important role in spreading
the infection as they are unaware that they are
sharing an infected files or emails with others.
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Worm are designed like viruses and so considered
as its sub-category. But the way it works make it
different, worms can spread from one machine to
another unaided as they file or information
transport features. Not only this they can
duplicate itself for instance if a single worm is
sent out by a machine it can easily send out
hundreds or thousands of copy itself resulting
in huge devastating effects. To understand things
better lets take for an example a worm can send
a copy of itself to all the e mail address
listed. From there it replicates itself and
sends itself to other in the address book of the
recipient and this process goes on. Due to the
way, it works worms tend to consume too much
system memory (or network bandwidth), causing Web
servers, network servers and individual
computers to be unresponsive. The most recent
worm attack was designed to get into the system
and allowed malicious users to control the
computer remotely.
Trojan horse is different than virus and worm.
It is a destructive program that looks as a
legitimate application. Unlike worms, Trojan
horse cant replicate itself but can be
destructive. Trojans opens a backdoor entry to
your computer which gives malicious
users/programs access to your system, allowing
confidential and personal information to be theft.
Virus
Worm
Trojan Horse
Cannot spread from one computer to another
without human intervention
Can spread from one system to another by itself
Cannot replicate itself
Trojan Horse is hard to detect and Is very
destructive
Viruses have different level of threats
Worms are destructive and dangerous
Trojan Horse doesnt need much system resources
as it looks as genuine application but works
differently
Viruses doesnt use too much of system resources
Worms take up a lot of bandwidth and makes the
system unresponsive
Worms can be attached to anything, specially they
are sent out as e mail attachment
Trojan Horse hides under a genuine application
and spreads infection
Virus attached to executable file
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Steals information and makes system vulnerable
Makes system slow sluggish and can even use it as
a bot
Trojan Horse opens a backdoor for malicious
programs
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Hope after reading the article you can know the
difference between these threats. They all cause
damage to the machine but the way they work is
not the same. Virus and trojan horse cannot
replicate itself whereas worms can. Viruses
cannot execute itself but others can so now you
very well know these threats only look alike but
they arent.