Type File virus
Creator M. Vallen
Date Discovered 1987.10
Place of Origin West Germany
Source Language Pascal
Platform DOS
File Type(s) .com
Infection Length 12,032 bytes
Reported Costs

Numberone is an early DOS virus from 1987. When Numberone is executed, it finds the first uninfected .com file in the current directory and overwrites them with a copy of itself. Files smaller than the virus's 12,032 bytes will become that size. It displays the text in yellow "This File Has Been Infected by Number One!".

Most variants of the virus do not differ significantly from the original. The primary differences are the virus size or some part of the message. One variant known as AIDS (no relation to AIDS-II) displays a message saying "Your computer now has AIDS". Variants were produced as late as 1992.



Patricia Hoffman. Online VSUM, Number One Virus.

-. -, AIDS Virus.

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