MDEF
{{Short description|Computer virus}}
{{Infobox computer virus
| Fullname = MDEF
| Common name = MDEF
| Technical name = MDEF
| Family = Unknown
| Aliases = Garfield
Top Cat
| Classification = Virus
| Type = Macintosh
| Subtype = Nuisance
| IsolationDate = May 1990
| Isolation = Ithaca, New York
| Origin = Ithaca, New York
| Author = Same author as CDEF
}}
MDEF was a computer virus affecting Macintosh machines. There are four known strains. The first, MDEF A (aka Garfield), was discovered in May 1990. Strains B (aka Top Cat), C, and D were discovered in August 1990, October 1990, and January 1991, respectively.
MDEF A, B, and C can infect application files and system files, and sometimes document files as well. The D strain will infect only applications. None of the viruses were designed to do damage, but they often do. MDEF D can sometimes damage applications beyond repair.
Quick action by computer security personnel and the New York State Police resulted in identification of the author, a juvenile. This was the same person responsible for writing the CDEF virus.
References
- Norstad, John. The Viruses. Disinfectant 3.7.1 ©1988-1997 Northwestern University.