In November of 1983, USC academic advisor Len Adleman minted the term "virus" because a computer virus multiplies itself within the bowels of a computer system just as the flu and the common cold replicate in human bodies. Adleman made this revelatory observation in response to student Frederick Cohen, who installed a virus during a university presentation.

Numerous viruses followed that first glimpse into technology's flawed future, some more insidious than others. Here we present an outline of influential viruses through the history of computers.

Long before the first Facebook post or YouTube video, BBN Technologies employee Bob Thomas created the first computer virus, a non-malicious program called Creeper. Reaper, a precursor to the modern antivirus software (although on a much smaller, more specific scale) sought and destroyed Creeper on DEC PDP-10 machines.

Elk Cloner
As a harbinger of future viral destruction, Elk Cloner served as the first wild computer virus. High school student Rich Skentra created Elk Cloner as a joke and released it through a game on a floppy disk. Skentra meant no harm, but when Cloner spread through Apple II computers via floppy disc, it sometimes replaced the contents of the media.

Originally created to prevent copyright infringement, Brain moved sectors of Microsoft computers and marked them as bad in the system, rendering those sectors unusable. It displayed a taunting message and inspired users from all over the world to complain to the creators, Pakistani brothers Basit Farooq and Amjad Farooq Alvi.

South African Friday the 13th Virus
Also known as Miami, the South African Friday the 13th virus launched in 1987 and ran on MS-DOS. It deleted every file it infected and featured a similar structure and pattern to the Jerusalem and Lehigh viruses, which appeared around the same time.

Zero Bug Virus
Stealth viruses, like Zero Bug introduced, deceptive programming that helped the infection remain hidden from computer users. The code implemented by the Zero Bug virus did not increase the host file's size, which made it more difficult to find and eradicate. Similar stealth viruses that appeared at the same time included Frodo and Dark Avenger, both of which launched in 1989.

Whale Virus
The significance of the Whale virus in 1990 lay in its size. It debuted as a self-modifying computer virus that slowed down the computer's operation significantly, resulting in screen flicker and delayed execution of files.

Get Password 1 Virus
In 1991, the first computer virus to steal passwords appeared in the form of Get Password 1. It was a derivative of the Jerusalem virus and focused on passwords culled from Novell NetWare.

The Concept computer virus accessed Microsoft Word documents and appeared in 1995. It was one of the first macro viruses, which run on the macro language within software, escaping detection. It also attained infamy because of its ability to infect multiple operating systems; since a macro virus depends on the software rather than the OS, it doesn't discriminate between devices.

Chernobyl Virus
Also known as the CIH virus, Chernobyl launched in 1998 and become one of the most nefarious computer viruses. It shipped with a drive firmware update and attacked both the boot drive and the BIOS. Versions of the virus still exist today.

Anna Kournikova Virus
The Anna Kournikova virus spread through email starting in 2001 and invoked the name of famous tennis star Anna Kournikova. The email included an attachment that purported to depict Kournikova, but instead contained a toolkit that plundered the recipient's email address book upon receipt and emailed itself to every destination it found.

The history of computer viruses mirrors the evolution of the internet itself, adapting to the new ways in which consumers use the web. Koobface, appearing in 2008, became one of the first viruses to attack social media users and profiles.

Viruses continue to evolve in creative (and nefarious) ways. Cryptolocker programs exemplify this fact in that the virus plants a program on the user's computer that demands a ransom in exchange for the decryption software necessary to remove it. Users either pay the ransom or lose all the data on their hard drives, such as family photos or corporate documents.

The only way for computer users to effectively protect themselves from computer viruses is to install antivirus software and to understand computer virus history. Just as viruses grow more sophisticated and complex, antivirus programs evolve, as well.

More Top Stories