How The First Personal Computer Virus Was A Prank Gone Wrong

BY Ray Stevens / ON Mar 10, 2021

How The First Personal Computer Virus Was A Prank Gone Wrong

Computer viruses are the bane of many computer systems and a mix of awareness and effective security systems are critical to avoiding a business being damaged in both financial and reputational terms by malware and bad actors.

A virus is defined as any computer program that replicates itself, usually by inserting its code into other computer programmes. They consist of three main parts:

  • Infection Mechanism – This is the part of the program which searches for potential files and disks which it can be copied into.
  • Trigger – Sometimes known as the logic bomb, this is when the virus is ready to activate and which conditions are required to make it activate, such as the date, time, another program existing or opening a particular file.
  • Payload – This is the dangerous part of the virus, where data is deleted, span is sent, data is encrypted or the virus simply spreads and replicates itself.

Whilst most viruses can be detected using firewalls and virus detection software, other viruses spread via people unknowingly downloading and activating them.

This is why raising awareness of potential threats to staff, through phishing simulation exercises and data integrity training.

However, the first notable PC virus spread largely by accident in 1986 and was a sign of the potential damage viruses could inflict.

The Elk Cloner Virus

Early viruses mostly consisted of academic exercises and were largely confined to early academic networks such as ARPANET. These include Creeper from 1971, which simply outputted the message “I’M THE CREEPER; CATCH ME IF YOU CAN”.

As well as this there was Rabbit in 1974, which self-replicated so quickly it could quickly crash a computer, as well as ANIMAL, the first-ever trojan virus. This was an animal guessing game that also copied itself to every directory the user had access to.

The first virus that would not be confined to the computer or network it was made on was 1982’s Elk Cloner, the first-ever boot sector virus that affected Apple II computers, then the most popular computer in schools in the United States.

It hooked into the boot sector of floppy disks (which would often be used in old computer systems to load programs) on a disk of a game that was set to play.

The virus would then spread to the computer’s RAM and would infect any other disk that was added, although due to a signature byte being added it would only be replicated once.

On the 50th time the game was booted, the payload released, which was a poem describing how the virus worked and described itself as “Elk Cloner: The program with a personality”.

The creator of the virus, a 15-year-old named Rich Skrenta, originally described it as a practical joke. He was somewhat infamous in his schools for altering the disks of his games to add taunting messages or simply to shut down, leading to many of his friends refusing to accept his disks.

To get around this, he would find a way to launch his messages automatically on an Apple II computer, and the virus worked to upset many people he knew.

Little did he know how much the idea, and not just the virus would spread.

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