Because Tippett's predictions were based on the propagation rate of this particularly infectious bug, they probably overstated the potential growth rate of viruses. One of the peculiarities of viruses that Tippett overlooked is that most remain localized, causing infection on a limited number of machines, sometimes on just a single site. So far only about fifty viruses have propagated rapidly and spread from their spawning ground to computers throughout the world. The rate of propagation seems to be a matter of luck. Through an unpredictable combination of circumstance and chance, some viruses are destined to wither away in parochial isolation, while others achieve a sort of international notoriety. There seems little logic to which remain localized and which propagate.
In March 1989 a new virus was discovered in the United States, which was reported to have come to North America via Venezuela. Its payload was simple: it displayed the words Den and Zuk, converging from separate sides of the computer screen. The word Zuk was followed by a globe resembling the AT&T corporate logo. Inevitably, the virus became known as Den Zuk.
The bug was found to be relatively harmless. Like Brain, it nestled in the boot sector of infected diskettes, but changed their volume labels to "Y.C.I.E.R.P."
Its payload was set to trigger after what is known as a warm reboot--restarting the computer from the keyboard without using the power switch. Warm reboots are generally employed when the computer has frozen, or stopped--a fairly uncommon occurrence, so the payload wasnt triggered very often.
An Icelandic virus researcher, Fridrik Skulason, surmised that the character string "Y.C.I.E.R.P" could be an amateur radio call sign. He looked up the sign in the International Callbook and found that it was attributed to an operator in Bandung, a city on the island of Java, in Indonesia. Skulason wrote to the operator, Denny Ramdhani, who replied with a long and detailed letter. He was, he admitted, the author of Den Zuk: "Den" was an allusion to his first name; "Zuk" came from his nickname, Zuko, after Danny Zuko, the character played by John Travolta in the film Grease. He had written the virus in March 1988, when he was twenty-four, "as an experiment." He wanted, he said, "to 'say hello' to other computer users in my city. I never thought or expected it to spread nationwide and then worldwide. I was really surprised when my virus attacked the U.S.A."
If Denny was surprised, the computer industry was flabbergasted. Den Zuk was neither a particularly infectious bug, nor was it grown in a locale that could be said to be within the communication mainstream. Bandung, for all of its exotic charm, is not a city normally associated with high-technology industries. Denny's virus traveled simply because it got lucky.
Viruses are unguided missiles, so it seems almost as likely that a bug launched from an obscure Indonesian city will hit targets in North America as one set off from, say, Germany. Nor is the sophistication of the bug any arbiter of its reach: Den Zuk was a simple virus, without any real pretension to what is known as an infection strategy.
The universality of the PC culture is reflected by the provenance of viruses. In Britain, New Scotland Yard's Computer Crime Unit recently compiled a list of the country's most troublesome bugs, which originated in places as diverse as New Zealand, Taiwan. Italy, Israel (the Jerusalem virus), Austria, Pakistan (Brain), Switzerland, India, and Spain--as well as a couple from the United States and even one that is believed to be from China.
The increasing links between virus writers in different parts of the world is demonstrated by the growing number of adaptations of existing viruses. The Vienna virus, which Ralph Burger had included in his Das grosse Computerirenbuch spawned a whole series of knockoffs, with slightly differing payloads and messages. As did the Jerusalem virus: there are now perhaps a hundred variants, all based on the one prototype. The knockoffs come from all over the world: Australia, the Netherlands, the republics of the former Soviet Union, Britain, South Africa, Czechoslovakia, Malaysia, Argentina, Spain, Switzerland, the United States--the list is only slightly shorter than the membership of the U.N. Some of the new variants are just jokes, and play tunes, but others are even more destructive than the original.
