:worm: [from `tapeworm' in John Brunner's novel "The
Shockwave Rider", via XEROX PARC] n. A program that propagates
itself over a network, reproducing itself as it goes. Compare
{virus}. Nowadays the term has negative connotations, as it is
assumed that only {cracker}s write worms. Perhaps the
best-known example was Robert T. Morris's `Internet Worm' of 1988,
a `benign' one that got out of control and hogged hundreds of
Suns and VAXen across the U.S. See also {cracker}, {RTM},
{Trojan horse}, {ice}, and {Great Worm, the}.
-- The AI Hackers Dictionary
Trojan horse: [coined by MIT-hacker-turned-NSA-spook Dan Edwards]
n. A malicious, security-breaking program that is disguised as
something benign, such as a directory lister, archiver, game, or
(in one notorious 1990 case on the Mac) a program to find and
destroy viruses!...