virus
(By 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 horse}s. 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 {display hack}s). Many nasty
viruses, written by particularly antisocial {cracker}s, do
irreversible damage, like deleting all the user's files.
In the 1990s, viruses have become a serious problem,
especially among {IBM PC} and {Macintosh} users (the lack of
security on these machines enables viruses to spread easily,
even infecting the operating system). The production of
special {antivirus 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 into
popular usage (where it is often incorrectly used to denote a
{worm} or even a {Trojan horse}).
See {boot virus}, {phage}. Compare {back door}. See also
{Unix conspiracy}.
[{Jargon File}]
(1995-01-31)