What Was the First Computer Virus?
Answer: The Creeper Virus
While the technical definitions for computer virus, worm, and malware might have a little overlap, it’s generally accepted that the first type of computer “virus” occurred in 1971 on ARPANET, the scientific/military network that preceded the modern internet. Creeper was an experimental self-replicating program that infected DEC computers across the network — this would be considered a computer worm today.
Written by Bob Thomas at the BBN Technologies lab, Creeper propagated itself throughout ARPANET by exploiting a vulnerability in DEC PDP-10 computers running the TENEX operating system. The worm wasn’t malicious and, upon gaining access to a machine and replicating itself, broadcast “I’m the creeper, catch me if you can!” on the terminal screen. The first virus removal program, dubbed The Reaper, soon followed, designed to ferret out Creeper infections.
Note: the term “computer virus” usually means a computer program that can replicate itself and spread from one computer to another. In modern terms, this is usually done by infecting a file, so a worm is not necessarily a virus. The term computer virus is also used in a more broad sense to describe malware, so the Creeper Virus is still a valid choice for the first virus — plus, it was created 10 years before the next viruses (Elk Cloner and Brain), making it a big milestone.