Worms are quite different
from virus as they are generally doing affect files as much. They don’t
delete files. But their aim is to block the network and have a capability to
bring down a whole network system as well. They don’t need a specific
excitation from the user. They can run as standalone applications without
the intervention from the user.
Their working methodology is to first find out a specific
vulnerability in the system so that they can easily hijack the system and
then apply the same method for other subsequent systems. This leads to
excessive use of the network resources which may lead to collapse of the
system as a whole.
They can also launch DoS (Denial of Service) attacks
on the network and flood the system
How do worms spread?
Worms
spread through email attachments. Once they gain accesses to a particular
system they immediately send out copies of themselves on to the network and
thus overload the network infrastructure. And when their attacks intensify,
an access to the network is denied.
They have a capability of hiding
from various antivirus software and scanners. This is due to the fact that
they get easily embedded in programs which are then distributed. Thus they
are able to penetrate most network firewalls.
The Melissa and ILOVEYOU email viruses are examples of
worms. In 1999, the Melissa worm
caused $80 million in damages through spreading by sending mails to 50
contacts of the outlook.
In 2000 ILOVEYOU launched a similar attack as with the
Melissa virus. But this virus also captured sensitive information like email
passwords and send it back to it’s creator.
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