virus, worm, trojan definitions (was: Re: Virus attacking Mac OS X found)

nomail@xxxxxxxxxxxxxx (Johan W. Elzenga) writes:

If I understand it correctly, it's more than a trojan. It DOES
replicate itself by means of iChat (if you use that and have a buddy
list). That makes it perhaps a 'viral trojan'? ;-)

In computer security technology, a virus is a self-replicating
program that spreads by inserting copies of itself into other
executable code or documents. A computer virus behaves in a way
similar to a biological virus, which spreads by inserting itself
into living cells.

http://en.wikipedia.org/wiki/Computer_virus

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.

http://en.wikipedia.org/wiki/Computer_worm

In the context of computer software, a Trojan horse is a malicious
program that is disguised as legitimate software. The term is
derived from the classical myth of the Trojan horse. They may look
useful or interesting (or at the very least harmless) to an
unsuspecting user, but are actually harmful when executed.

http://en.wikipedia.org/wiki/Trojan_horse_(computing)

A trojan could be considered a 'delivery method' for either a worm or
a virus. How the malicious code propagates once it is delivered can be
as a virus and / or a worm: overwritting executable files so that the
malicious code is run when you run the program is a virus, a worm can
run on itself once it's started up, and doesn't need the user to
execute a command to do anything; nothing precludes the malicious code
from doing both. A lot of worms nowadays (especially on Windows) seem
to be separate executables that are run / started up during the
operating system boot up.

While this may seem like people are just being pedantic, these terms
do have specific technical meanings:

Language is a finger that points to the reality it seeks to
describe.
-- Steven Fortney


--
David Magda <dmagda at ee.ryerson.ca>
Because the innovator has for enemies all those who have done well under
the old conditions, and lukewarm defenders in those who may do well
under the new. -- Niccolo Machiavelli, _The Prince_, Chapter VI
.

Relevant Pages

  • Re: Linux virus question
    ... But a worm can carry a virus and may ... but not "*deliberately* execute the damn thing". ... the USER SAVING a mail attachment. ...
    (alt.os.linux)
  • Re: What is the difference between a worm and a trojan ?
    ... I know the difference between a virus and a trojan. ... >> difference between a worm and a trojan? ... > host system, which will then in turn attempt to infect other systems, etc., ad ...
    (comp.security.misc)
  • Oxygen3 24h-365d [Weekly virus report - 10/26/03]
    ... Lohack.C spreads via e-mail and across network drives. ... this worm tries to trick users by referring to the Spanish Information ... The fourth malicious code in today's report is a Trojan called Sdbot.N. ... Vix.A is a virus with worm characteristics that infects PE files ...
    (microsoft.public.security.virus)
  • Re: Linux virus question
    ... >>so the likelihood of affecting system files ... a worm is not a virus. ... that can be a hacker - as suggested below, but the hacker has to execute ...
    (alt.os.linux)
  • Re: What is the difference between a worm and a trojan ?
    ... I know the difference between a virus and a trojan. ... | the difference between a worm and a trojan? ... Worm, Trojan horse, virus. ...
    (microsoft.public.security)