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The Evolution of Viruses

1983: Virus researcher Fred Cohen coins the term "computer virus" in a research paper.

1987: Brain, the first computer virus, is released. It infects the boot sector of 360KB floppy disks and uses stealth techniques to leave the computer unaware of it. Stoned (the first virus to infect the Master Boot Record) is released. It scrambles the hard drive's MBR, preventing a system from booting.

1988: The first antivirus software is released by an Indonesian programmer. It detects the Brain virus, excises it from a computer, and immunizes the system against further Brain attacks.

The Internet Worm is released onto the nascent Net and brings down about 6000 computers.

1989: Dark Avenger appears. It infects programs quickly, but the subsequent damage happens slowly, permitting the virus to go undetected for a long time.

IBM releases the first commercial antivirus product. Intensive antivirus research commences.

1990: Sophisticated virus types such as polymorphic viruses (which modify themselves as they spread) and multipartite viruses (which infect multiple locations in a machine) appear.

Virus-exchange bulletin boards become popular methods for writers of viruses to post and exchange source code.

1991: Virus construction kits, which allow almost anyone to build a virus easily, appear on virus exchange boards.

At the beginning of the year, a modest 9 percent of companies polled have experienced a virus outbreak. By the end of the year, that figure has leaped to 63 percent.

1992: Michelangelo, the first virus to cause a media frenzy, is set to overwrite parts of infected hard drives on March 6, the Renaissance artist's birthday. Sales of antivirus software soar, though only a few cases of actual infection are reported.

1994: The author of a virus called Pathogen in England is tracked down by Scotland Yard and sentenced to 18 months in jail. This marks the first time a virus writer is prosecuted for promulgating damaging code.

1995: Concept, the first macro virus, appears. Written in Microsoft's Word Basic language, it can run on any platform that Word runs on--PC or Macintosh. Concept triggers an explosion in the number of viruses written, because macro viruses are so easy to create and disseminate.

1999: The Chernobyl virus, which renders the user's hard drive and data inaccessible, hits in April. Though it infects few computers in the United States, it inflicts widespread damage overseas. China sustains damages of more than $291 million. Turkey and South Korea are also hit hard.

The Melissa virus strikes hundreds of thousands of computers worldwide. It uses Microsoft Outlook to mail itself to 50 people in a user's address book, making it the first virus capable of jumping from one computer to another on its own.

2000: The LoveLetter virus, launched from the Philippines, sweeps over Europe and the United States within 6 hours. It infects some 2.5 million to 3 million machines, causing an estimated $8.7 billion in damage.

--Some information taken from Joe Wells's timeline.