Generally accepted as the first virus is the Creeper Worm, developed in 1971 by Bob Thomas. It was not however designed maliciously or with any intent do damage. Creeper was a self replicating program. Creeper gained access via the ARPANET and copied itself to the remote system where the message, “I’m the creeper, catch me if you can!” was displayed. The Creeper would start to print a file, but then stop, find another Tenex system, open a connection, pick itself up and transfer to the other machine (along with its external state, files, etc.), and then start running on the new machine, displaying the message. The program rarely if ever actually replicated itself, rather it jumped from one system to another, attempting to remove itself from previous systems as it propagated forward, thus Creeper didn’t install multiple instances of itself on several targets, actually it just moseyed around a network. A program called Reaper was created to delete creeper.
In 1974 the Wabbit Virus, was created (see also fork bomb), Wabbit was a self-replicating program, that made multiple copies of itself on a computer until it bogs down the system to such an extend that system performance is reduced to nil and the computer eventually crashes. This virus was named wabbit because of the speed at which it was able to replicate.
In 1986 the Brain Boot Sector Virus showed up. Brain is considered to be the FIRST IBM PC Compatible virus. It infected the boot sector of MS-DOS systems. The Brain virus is responsible for the first IBM PC virus epidemic. The Brain virus even came with contact information for the authors who created it as well as a message that notified the user that their machine was infected:
Welcome to the Dungeon Â© 1986 Basit * Amjad (pvt) Ltd. BRAIN COMPUTER SERVICES 730 NIZAM BLOCK ALLAMA IQBAL TOWN LAHORE-PAKISTAN PHONE: 430791,443248,280530. Beware of this VIRUS.... Contact us for vaccination...
There was a legitimate reason for the message appearing as the Brain virus was originally used to track software (a heart monitoring program developed for the Apple ][e series, computer pirates were distributing copies of the disks. The tracking program was developed to stop and track illegal copies. Another programmed copied the technique for DOS and that’s how it became the Brain virus.