Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!ames!saturn!xanthian
From: xanthian@saturn.ADS.COM (Metafont Consultant Account)
Newsgroups: comp.misc
Subject: Re: Why "worm" instead of "germ"
Keywords: virus vs. worm
Message-ID: <10493@saturn.ADS.COM>
Date: 18 Jan 90 10:04:47 GMT
References: <1476@umigw.MIAMI.EDU> <76929@looking.on.ca> <77443@looking.on.ca>
Organization: Advanced Decision Systems, Mt. View, CA (415) 960-7300
Lines: 41

In article <77443@looking.on.ca> brad@looking.on.ca (Brad Templeton) writes:
=While it's clear that the Morris program didn't act as a "virus" by grafting
=itself into another program, why the term "worm?"
=
=A worm implies something that crawls around with one head, and possibly
=a tail -- to me this would be a program that moved around from system to
=system, never staying in one place.
=
=Morris' program was a "germ" or "bacterium."  It would infect a system,
=and then attempt to breed to neighbours by making copies of itself.
=Like some germs, it affected its hosts by swamping them.
=
=So why "worm?"
=-- 
=Brad Templeton, ClariNet Communications Corp.-- Waterloo, Ontario 519/884-7473


I don't know why the term was used, but it supplies a very appropriate
visual metaphor.

Morris' (putative) program functioned by pushing a small part of itself
forward, forcing it into a target system through treachery having to do
with overflowing a field unprotected by a length check to overwrite part of
the stack, which changed the systems normal execution to execute some of
the attacking code, then, when the "head" of the beast was successfully in,
it "sent back" for the rest of the code, which was forwarded and loaded to
complete a successful invasion.

Compare that to the nightcrawler forcing itself through a hole smaller than
its body's rest cross section:  it uses its body to push hard; first the
head emerges, then the rest of the body follows though the passage already
broached, at last the worm is on this side of the barrier; and you may be
happier with the choice of terms.

--
Again, my opinions, not the account furnishers'.

xanthian@well.sf.ca.us  xanthian@ads.com (Kent Paul Dolan)
Kent, the (bionic) man from xanth, now available as a build-a-xanthian
kit at better toy stores near you.  Warning - some parts proven fragile.
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