1990
MDEF (also known as Garfield) and its variants emerged on the malware scene in 1990 to infect application and system files in Macintosh 128K and 512K, 512KE, Mac Plus, SE, SE/30, II, IIx, IIcx, IIci and IIfx computers. Coded by an Ithaca, N.Y. teenager and identified at nearby Cornell University, the malware didn’t cause intentional damage but could cause crashes and damage files.