Mathematician John von Neumann, dubbed father of game theory, first theorized the concept of a computer virus in the late 1940s and published an article on his theory in 1966. His vision of a virus was as a self-replicating automatic entity and in 1971 the Creeper Virus, the first real computer virus, was exactly that. An entire program, nicknamed the Reaper Program, was designed by information security professionals to prevent the Creeper Virus from copying itself into systems and halting the ability to process.

A high school student programmed the first personal computer virus in 1981, named The Elk Cloner, as a practical joke and spread it via floppy disc. The virus was attached to a computer game for the Apple DOS system, a computer system that was very vulnerable to infection due to its storage capabilities. The Elk Cloner is considered the first major computer virus outbreak in history, primarily because the public was not educated or familiar with the concept of viruses.

In 1986, the first virus 'The Brain' to specifically attack PCs via the DOS system was found. A floppy disk-based virus, worked by increasing its code volume each time the host program was run. The result was floppy disks would fill up and be rendered unusable, but essentially harmless. It was also the first stealth virus, designed to hide itself by attaching to relatively unused code, making it invisible to consumer-accessible debug programs. Notable factor about the Brain was that it inspired information technicians at IBM to release the first antivirus software for public use in 1987.

Use of signatures to detect the virus was not only the notable point but also the beginning of the chase by design these signatures were used to blacklist. meaning an update needed for newer detection and asking the user for consent if it was done to whitelist. This consent is now standard in all operating systems almost 30 years after. though now, it's almost useless as many techniques today piggyback on legitimate softwares by exploitation of their vulnerabilities.

Zero day exploits!