This timeline of computer viruses and worms presents a chronological timeline of noteworthy computer viruses, computer worms, Trojan horses, similar malware, related research and events.
1960s
John von Neumann's article on the "Theory of self-reproducing automata" is published in 1966. The article is based on lectures given by von Neumann at the University of Illinois about the "Theory and Organization of Complicated Automata" in 1949.
1970s
1970
The first story written about a computer virus is The Scarred Man by Gregory Benford.
1971
The Creeper system, an experimental self-replicating program, is written by Bob Thomas at BBN Technologies to test John von Neumann's theory. Creeper infected DEC PDP-10 computers running the TENEX operating system. 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 Reaper program was later created to delete Creeper. At the University of Illinois at Urbana-Champaign, a graduate student named Alan Davis (working for Prof. Donald Gillies) created a process on a PDP-11 that (a) checked to see if an identical copy of itself was currently running as an active process, and if not, created a copy of itself and started it running; (b) checked to see if any disk space (which all users shared) was available, and if so, created a file the size of that space; and (c) looped back to step (a). As a result, the process stole all available disk space. When users tried to save files, the operating system advised them that the disk was full and that they needed to delete some existing files. Of course, if they did delete a file, this process would immediately snatch up the available space. When users called in a system administrator (A. Ian Stocks) to fix the problem, he examined the active processes, discovered the offending process, and deleted it. Of course, before he left the room, the still existing process would create another copy of itself, and the problem wouldn't go away. The only way to make the computer work again was to reboot.
1972
The science fiction novel, When HARLIE Was One, by David Gerrold, contains one of the first fictional representations of a computer virus, as well as one of the first uses of the word "virus" to denote a program that infects a computer.
1973
In fiction, the 1973 Michael Crichton movie Westworld made an early mention of the concept of a computer virus, being a central plot theme that causes androids to run amok. Alan Oppenheimer's character summarizes the problem by stating that "...there's a clear pattern here which suggests an analogy to an infectious disease process, spreading from one...area to the next." To which the replies are stated: "Perhaps there are superficial similarities to disease" and, "I must confess I find it difficult to believe in a disease of machinery." (Crichton's earlier work, the 1969 novel The Andromeda Strain and 1971 film were about an extraterrestrial biological virus-like disease that threatened the human race.)
1974
The Rabbit (or Wabbit) virus, more a fork bomb than a virus, is written. The Rabbit virus makes multiple copies of itself on a single computer (and was named "Rabbit" for the speed at which it did so) until it clogs the system, reducing system performance, before finally reaching a threshold and crashing the computer.
1975
April: ANIMAL is written by John Walker for the UNIVAC 1108. ANIMAL asked several questions of the user in an attempt to guess the type of animal the user was thinking of, while the related program PERVADE would create a copy of itself and ANIMAL in every directory to which the current user had access. It spread across the multi-user UNIVACs when users with overlapping permissions discovered the game, and to other computers when tapes were shared. The program was carefully written to avoid damaging existing file or directory structures, and to avoid copying itself if permissions did not exist or if harm would result. Its spread was halted by an OS upgrade that changed the format of the file status tables PERVADE used. Though non-malicious, "Pervading Animal" represents the first Trojan "in the wild". The novel The Shockwave Rider by John Brunner is published, coining the word "worm" to describe a program that propagates itself through a computer network.
1977
"The Adolescence of P-1" novel, describes a worm program which propagates through modem-based networks, eventually developing its own strategy-developing AI, which deals with cross-hardware and cross-os issues, eventually infecting hardware manufactures and defense organizations.