Illness Is Fast Becoming Apt Metaphor for Computers

June 14, 1999

Illness Is Fast Becoming Apt Metaphor for Computers

By JOHN MARKOFF

AN FRANCISCO -- The implications of the malicious software program that wove its way around the globe last week struck home for Bernardo Huberman, a physicist at Xerox, in the form of a terse voice mail he received at work on Thursday.
"Our computer system administrators sent me a message saying, 'The worm has hit Xerox, but we've hunted it down and killed it,'" he recalled.

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To Huberman, a researcher who has studied the behavior of computer networks for more than a decade, the biological allusions were an apt and perhaps chilling reminder that the explosive growth of the Internet has numerous parallels to natural systems -- and many are not reassuring.
"I believe that we are indeed living in a computational ecosystem which is more and more globally cross-linked," he said. Or to put it more simply, "It's an amazing system, and it's very vulnerable."
In a world where computers, once isolated work tools, are increasingly the very engine driving modern business life, computer researchers say they are detecting an ominous trend toward programs that mimic viruses and pestilence in the physical world.
The latest focus of concern is a program known among computer researchers as a worm. The recent one was apparently conceived in Israel and quickly spread to Europe and the United States, mailing itself from computer to computer and destroying its victims' files along the way. Called Explore.exe -- for the name of the file it contained that set off the damage -- the worm has affected thousands of computers worldwide and forced a number of corporations to abruptly shut their e-mail systems, in a frantic effort to control the spread of the infection.
Like biological diseases, which exploit the most basic mechanism of life -- the power of DNA to replicate itself -- a subculture of modern virus-writing now manipulates that same power of replication within the world of interconnected computers.
While the dominance of a single computing environment -- the one powered by Microsoft software and Intel chips -- offers the benefits of compatibility among machines, some say it may share the vulnerabilities of fields planted with just one crop.
"The analogies are extremely close," said Richard Dawkins, a biologist at Oxford University. "When you make machines that are capable of obeying instructions slavishly, and among those instructions are 'duplicate me' instructions, then of course the system is wide open to exploitation by parasites."
Some computer scientists believe that in the rise of the Internet and the World Wide Web, society has struck a Faustian bargain -- gaining the potential of robotic software agents, which can flit from computer to computer to do their masters' bidding almost intelligently, but accepting as well the darker prospect of software infections that can sow the destruction of cybernetic plagues.
"This may simply be the price you will have to pay for having the flexibility, adaptability, autonomy of this new networked world," said Kevin Kelly, author of "Out of Control: The New Biology of Machines, Social Systems and the Economic World" (Addison Wesley, 1994).
Biological metaphors used to describe the hostile software are only that, and the analogies do break down because the so-called computer viruses are man-made, not natural, and are frequently designed to be destructive.

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But some researchers assert that such diseases are a direct outgrowth of the remarkable complexity emerging in the realm of networked computers. Increasingly, they say, Internet viral issues will come to resemble the modern world's perpetual public health crisis.
"You need to look at this the way the Centers for Disease Control approach things," said Vernor Vinge, a computer scientist at San Diego State University. "There are always new problems on their threat board."
Computer scientists have known about these risks since the first worm programs were written by researchers at the Xerox Corp.'s Palo Alto Research Center in the early 1970s.
Experimenting with the power of networked computers, scientists fashioned a wide variety of helpful programs, ranging from "vampire" worms that kept the network's computers laboring late at night to "diagnostic" worms that efficiently spread software repairs around the research center.
But a software error in one of the lab's early worms caused the program to run amok, crashing computers everywhere in the building.
Today computer researchers debate what distinguishes worms from viruses, both metaphors drawn from science fiction. The term "worm" first appeared in John Brunner's 1975 novel "Shockwave Rider" (Del Rey Books) while "virus" first appeared in a computer context in David Gerrold's "When Harley Was One" (Ballantine, 1972).
Traditionally, the term "virus" has been used to describe software codes that infect computers by attaching themselves to documents or programs that are passed along. "Worms," by contrast, have been self-propelling, that is, a program sent within the attachment can then send itself along without any action by the person who receives it.
But the most recent generation of malicious programs -- like the Melissa virus, which spread rapidly around the world in late March, and Explore.exe, the worm that emerged in Israel last Monday -- blend aspects of both.
The world of computer networks has not yet produced the most telling biological analogy -- evolution. But a particular class of hostile programs known as polymorphic viruses has been designed since 1993, with the ability to mutate to evade the pattern detection capabilities of modern antivirus scanning programs.
Increasingly, antivirus researchers are also turning to biological solutions to face down hostile software codes. For example, last month the Intel Corp., IBM and the Symantec Corp. jointly released a new antivirus software technology they call a "Digital Immune System."
Just as a biological immune system offers a systemic approach to illness, the new software shifts the antivirus response from the PC to an entire corporation's network, automatically relaying suspect programs for inspection and directly immunizing individual computers.
There have been other attempts to build systems that are immune from security threats. For example, the original intent of the Java programming language was to prohibit the kind of file destruction wreaked last week by creating a "sandbox" that limits a program's destructive capabilities.
Strikingly, the rapid spread of last week's outbreak was made possible because most of the world's users of personal computers now run Microsoft software. The destructive program was written to destroy documents written in widely used Microsoft applications like Word, Excel and Power Point and certain programming files.
"This is the classic result of a computer monoculture," said W. Daniel Hillis, a computer scientist at Walt Disney's Imagineering unit. Like agricultural ecologies that become fragile and unstable when relying on only one or a few different crops, so the modern computer world is vulnerable to the degree it relies on Microsoft's software.
Noting that the worm had attacked large American military contractors, including Boeing and General Electric, Art Amolsch, editor of FTC Watch, a Washington policy newsletter, suggested that the government should insure software diversity among its agencies and contractors.
"I propose that no government agency be allowed to run more than 34 percent of its personal computers on one proprietary operating system by a date certain," he said.

To Hillis, who in the 1980s experimented with advances in software programs using "evolutionary" techniques in which the programs adapt to their environment, a transition is under way in which computers will be viewed less like mechanical devices and more like biological organisms, which more easily accommodate imprecision and failure.
"Today we have the fragility of an engineered system where every part works" but the system itself can fail, he said. "But in the future we're going to engineer systems with the expectation that everything is broken all the time. That's how we treat biological systems today."

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