| A
computer worm is a self-replicating computer
program, similar to a computer virus. A
virus attaches itself to, and becomes part
of, another executable program; however,
a worm is self-contained and does not need
to be part of another program to propagate
itself. They are often designed to exploit
the file transmission capabilities found
on many computers.
The
first worm to attract wide attention, the
Morris worm, was written by Robert Tappan
Morris, Jr. at the MIT Artificial intelligence
Laboratory. It was released on November
2, 1988, and quickly infected a great many
computers on the Internet at the time. It
propagated through a number of bugs in BSD
Unix and its derivatives. Morris himself
was convicted under the US Computer Crime
and Abuse Act and received 3 years' probation,
community service and a fine in excess of
$10,000.
In
addition to replication, a worm may be designed
to do any number of things, such as delete
files on a host system or send documents
via email. More recent worms may be multi-headed
and carry other executables as a payload.
However, even in the absence of such a payload,
a worm can wreak havoc just with the network
traffic generated by its reproduction. Mydoom,
for example, caused a noticeable worldwide
Internet slowdown at the peak of its spread.
A
common payload is for a worm to install
a backdoor in the infected computer, as
was done by Sobig and Mydoom. These zombie
computers are used by spam senders for sending
junk email or to cloak their website's address.
Spammers are thought to pay for the creation
of such worms, and worm writers have been
caught selling lists of IP addresses of
infected machines.Others try to blackmail
companies with threatened DDOS attacks.The
backdoors can also be exploited by other
worms, such as Doomjuice, which spreads
using the backdoor opened by Mydoom.
Additional
Definitions:
Adware
Browser
Hijacker
Browser Plugin
Dialer
Malware
Scumware
Spyware
Theifware
Trojan Horse
Computer Virus
Worm
This
article is licensed under the GFDL.
It uses material from the Wikipedia
article "computer worm"
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