System information

Threats to computer security 19
TYPE
NAME
DESCRIPTION
Email-
Worm
E-mail worms
E-mail worms infect computers via e-mail.
An infected message contains an attached file
containing a copy of a worm or a link to such file
uploaded to a website that, for example, can be
hacked or be a hacker's site itself. When you
open such attachment the worm gets activated;
when you click the link, download and then open
a file, the worm will also start performing its
malicious action. After this it will continue
reproduce through its copies finding other e-mail
addresses and sending infected messages to
them.
IRC-
Worms
IM worms
Worms of this type get into computers through
Internet Relay chats - service systems used to
communicate with other people via internet in
real-time format.
This worm publishes in the internet chat a file
with its copy or a link to such file. When a user
downloads and opens such file, the worm will be
activated.
Net-
Worms
Network worms
(worms residing in
computer
networks)
These worms are distributed via computer
networks.
Unlike worms of other types, network worms are
propagated without the user's participation.
They search in the local area networks
computers using programs containing
vulnerabilities. For this it sends a special
network packet (exploit) containing its code or a
part of such code. If there is a vulnerable
computer in the network, such computer will
receive such packet. Once the worm fully
penetrates the computer, it gets activated.