Ten computer viruses that changed the world

Ten computer viruses that changed the world

Summary: In the malware arms race that has seen digital villains stay one step ahead of the good guys, some landmarks stand out. ZDNet UK picks the most important, and most unexpected, unpleasant surprises to confront IT users

TOPICS: Security

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  • Brain virus

    It's almost 25 years since the first PC computer virus left users looking at corrupted floppies, lost work and perplexing messages. In that time, the state of the art in automated malfeasance has progressed to the point that it's part of the armoury of international geopolitics. Stuxnet, while still mysterious, left nobody in any doubt that viruses and worms can be used in the highest-stake game there is.

    Along the way, hundreds of millions of infections have taken place, billions of dollars have been lost in productivity and broken systems, and the anti-malware industry has grown to become a significant player in the IT market. It's not over yet: perhaps it never will be, but the history of malware is a fascinating insight into the technology and culture of the digital world.

    1. Brain (1986)
    It sounded like science fiction, but it was all too real. Basit and Amjad Farooq Alvi, a pair of software programmers from Pakistan, became annoyed at people duplicating their products and created what was supposed to be a kill switch for illicit copies. But the design was flawed; the anti-copy software could duplicate itself — and did.

    The first worldwide PC virus, Brain worked by changing the boot sector of a floppy. When an infected floppy was put into a computer, it installed Brain in the computer's memory, from where it infected new floppies as they were inserted.

    The brothers included their names, address and phone numbers in the virus, ostensibly to offer their services to decontaminate infected computers. They subsequently regretted this.

    Photo credit: Avinash Meetoo/Wikipedia

  • Christmas Tree

    2. Christmas Tree (1987)
    A single design flaw can turn a harmless joke into a weapon. The Christmas Tree Exec was a script that ran under the Rexx language and did two simple things: it drew a Christmas tree, using text for graphics, and then sent a copy of itself to everyone in the target's email contacts list.

    The original started on Earn, the European Academic Research Network, and spread quickly to the US equivalent, Bitnet. The infection then hopped over to IBM's internal VNET, where it took advantage of the IBM habit of having really large address books.

    As the worm depended on running in an IBM mainframe environment, it didn't spread beyond those networks. It lasted six days on Bitnet and only four on VNET, where it was finally removed by shutting down the entire network.

    Photo credit: Sophos

  • Robert Morris

    3. Morris worm (1988)
    The first malware to be propagated widely via the internet, the Morris Worm or Great Worm hit around 6,000 of the 60,000 computers on the network in 1988.

    Robert Morris (pictured), then a student at Cornell University, maintains that his worm wasn't malicious, but was designed to measure the size of the internet. Others took a different view, as the worm used a batch of security flaws in Unix and was launched surreptitiously.

    It was certainly unwelcome, as it was far more aggressive at making copies of itself than it needed to be, often infecting machines multiple times, turning what might have been an easily contained annoyance into a powerful denial-of-service attack. Morris became the first person to be convicted under the 1986 US Computer Fraud and Abuse Act, and the incident led to the formation of the first Computer Emergency Response Team Coordination Center, CERT/CC.

    Photo credit: Trevor Blackwell/Wikipedia

Topic: Security

Rupert Goodwins

About Rupert Goodwins

Rupert started off as a nerdy lad expecting to be an electronics engineer, but having tried it for a while discovered that journalism was more fun. He ended up on PC Magazine in the early '90s, before that evolved into ZDNet UK - and Rupert evolved with them into an online journalist.

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