Computer virus Timeline 1949 Theories for self-replicating programs are first developed. 1981 Apple Viruses 1, 2, and 3 are some of the first viruses "in the wild," or public domain. Found on the Apple II operating system, the viruses spread through Texas A&M via pirated computer games. 1983 Fred Cohen, while working on his dissertation, formally defines a computer virus as "a computer program that can affect other computer programs by modifying them in such a way as to include …showed first 75 words of 732 total…

…showed last 75 words of 732 total…over 700,000 computers and caused upwards of 2 billion in damages. A worm spreads through external and (then) internal computer networks, as opposed to a virus which infects computers via email and certain web sites. Code Red took advantage of a vulnerability in Microsoft's Windows 2000 and Windows NT server software. Microsoft developed a patch to protect networks against the worm, and admits that they too were attacked. Other major companies affected include AT&T, and the AP.