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Undergound. Go to Table of Contents.

   On 16 October McMahon arrived at the office and settled into work,

   only to face a surprising phone call from the SPAN project office.

   Todd Butler and Ron Tencati, from the National Space Science Data

   Center, which managed NASA's half of the SPAN network, had discovered

   something strange and definitely unauthorised winding its way through

   the computer network. It looked like a computer worm.


   A computer worm is a little like a computer virus. It invades computer

   systems, interfering with their normal functions. It travels along any

   available compatible computer network and stops to knock at the door of

   systems attached to that network. If there is a hole in the security of

   the computer system, it will crawl through and enter the system. When it

   does this, it might have instructions to do any number of things, from

   sending computer users a message to trying to take over the system. What

   makes a worm different from other computer programs, such as viruses, is

   that it is self-propagating. It propels itself forward, wiggles into a

   new system and propagates itself at the new site. Unlike a virus, a worm

   doesn't latch onto a data file or a program. It is autonomous.7


   The term `worm' as applied to computers came from John Brunner's 1975

   science fiction classic, The Shockwave Rider. The novel described how

   a rebel computer programmer created a program called `tapeworm' which

   was released into an omnipotent computer network used by an autocratic

   government to control its people. The government had to turn off the

   computer network, thus destroying its control, in order to eradicate

   the worm.


   Brunner's book is about as close as most VMS computer network managers

   would ever have come to a real rogue worm. Until the late 1980s, worms

   were obscure things, more associated with research in a computer

   laboratory. For example, a few benevolent worms were developed by

   Xerox researchers who wanted to make more efficient use of computer

   facilities.8 They developed a `town crier worm' which moved through a

   network sending out important announcements. Their `diagnostic worm'

   also constantly weaved through the network, but this worm was designed

   to inspect machines for problems.


   For some computer programmers, the creation of a worm is akin to the

   creation of life. To make something which is intelligent enough to go

   out and reproduce itself is the ultimate power of creation. Designing

   a rogue worm which took over NASA's computer systems might seem to be

   a type of creative immortality--like scattering pieces of oneself

   across the computers which put man on the moon.


   At the time the WANK banner appeared on computer screens across NASA,

   there had only been two rogue worms of any note. One of these, the RTM

   worm, had infected the Unix-based Internet less than twelve months

   earlier. The other worm, known as Father Christmas, was the first VMS



   Father Christmas was a small, simple worm which did not cause any

   permanent damage to the computer networks it travelled along. Released

   just before Christmas in 1988, it tried to sneak into hundreds of VMS

   machines and wait for the big day. On Christmas morning, it woke up

   and set to work with great enthusiasm. Like confetti tossed from an

   overhead balcony, Christmas greetings came streaming out of

   worm-infested computer systems to all their users. No-one within its

   reach went without a Christmas card. Its job done, the worm

   evaporated. John McMahon had been part of the core team fighting off