[HaBi 2]    US. Computer Vandals Learn to Program Havoc

US. Computer Vandals Learn to Program Havoc By Mark McCain New York Times NEW YORK - A new breed of vandals, working within the vast network of U.S. computer "bulletin boards," are devising sophisticated software programs that erase and scramble the computer files of unsuspecting users. The practice is stirring mistrust and anger among business executives, academics and hobbyists who exchange free computer software on the bulletin boards. The vandals, using telephone links from their computers, are transferring the destructive programs onto the bulletin boards hoping to fool thousands of people into duplicate the programs to use in their own computers at great harm. "It's like poisoning the candy in the supermarket on Halloween," said Ross M. Greenberg, a Manhattan computer consultant. "I guess the people who devise these things take pleasure in destroving other people's work." The programs began appearing several Years ago and now have reached a level of sophistication that allows them to sometimes outfox computer experts who are on guard for them. Known as Trojan horses, Or More familiarly as Trojans the programs pretend to be something useful, like - word processor or game board. But they are electronic terrorists, ready to erase or scramble data stored in computers. Among the dozens of Trojans in circulation, some begin their destruction within minutes. Others perform as legitimate software for weeks or months. then touch off an electronic time bomb. "A person may lose five minutes of work or two years of work," said Mr. Greenberg, who maintains several "tools for defense" against Trojans, including a software program that alerts him to suspicious activity within his personal computer. Like hundreds of other computer enthusiasts across the country, Mr. Greenberg operates a computer bulletin board as a public service. Each sysop, shorthand for system operator, as the board operators are called, keeps a computer hooked up to a telephone line 24 hours a day, providing a "Over a year of work could be destroyed. If you're using the computer for business, how do you explain that sort of thing to your boss?" -- Eric Netvhouse, a computer expert clearing house for hundreds of free "public domain" software programs. People connect their computers into the bulletin boards, via teiephone-hookup devices called modems, both to donate programs and make copies of programs already posted on the boards. "The Trojan software represents another chapter in the exploits of the computer hackers, who invest countless hours n computerized subterfuge. "There are hacks out there who really amuse people with their cleverness," said Dave Bayer, an assistant professor of mathematics at Columbia University in New York - "But the hackers who write Trojans are simply mean-spirited and malicious. There's no skill involved in trashing people's hard disks." A hard disk, the primary storage unit of advanced personal computers, can hold the equivalent of 400 to 1,200 pages of single-spaced typewritten data. Like tape cassettes, the disks can be erased, intentionally or not. The Trojans work by giving the computer internal instructions, but while pretending to perform some legitimate function the instructions amount to electronic suicide. Some Trojans only scramble or erase the "file allocation table," the computer's index of where data are stored on a hard disk. A user can often still retrieve the data, although with difficulty. But others, after erasing the table, proceed to instruct the computer to do a "low-level format," or erasure, of the entire disk. "Conceivably, upwards or over a year of work could be destroyed," said Eric Newhouse, an 18-year-old computer expert in Los Angeles. "If you're using the computer for business, how do you explain that sort of thing to your boss?" Users are adjusting to computer terrorism by increasing security. Most bulletin board operators are beginning to check the identity of people who call up their boards. And they are testing suspicious programs. But even if a Trojan perpetrator were identified, it is uncertain whether any state or federal laws provide for prosecuting that person. "After you've been bit once," said Charles E. Rawis, a Manhattan computer user, "you look at every software program with a skeptical eye. But every once in a while, one of them still sneaks by. "

[HaBi 2]    US. Computer Vandals Learn to Program Havoc