virus
virus: n. [from the obvious analogy with biological viruses,
via SF] A cracker program that searches out other programs and
`infects' them by embedding a copy of itself in them, so that they
become Trojan horses. When these programs are executed, the
embedded virus is executed too, thus propagating the `infection'.
This normally happens invisibly to the user. Unlike a worm, a
virus cannot infect other computers without assistance. It is
propagated by vectors such as humans trading programs with their
friends (see SEX). The virus may do nothing but propagate itself
and then allow the program to run normally. Usually, however, after
propagating silently for a while, it starts doing things like
writing cute messages on the terminal or playing strange tricks with
the display (some viruses include nice display hacks). Many nasty
viruses, written by particularly perversely minded crackers, do
irreversible damage, like nuking all the user's files.
In the 1990s, viruses have become a serious problem, especially
among Wintel and Macintosh users; the lack of security on these
machines enables viruses to spread easily, even infecting the
operating system (Unix machines, by contrast, are immune to such
attacks). The production of special anti-virus software has become
an industry, and a number of exaggerated media reports have caused
outbreaks of near hysteria among users; many lusers tend to blame
_everything_ that doesn't work as they had expected on virus
attacks. Accordingly, this sense of `virus' has passed not only
into techspeak but into also popular usage (where it is often
incorrectly used to denote a worm or even a Trojan horse). See
phage; compare back door; see also Unix conspiracy.
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