The Israeli (aka Hebrew University, Jerusalem, or Friday the 13th) Virus

This cleverly devised program was discovered at the Hebrew University in
Israel in 1987 and demonstrated the potential of viruses as a weapon of
terrorism and political protest.  It contaminated IBM and IBM-compatible
systems at a number of other institutions and on personal computers elsewhere
in Israel, before spreading further afield.

The perpetrator's main plan was to wipe out files on Friday, May 13, 1988--
that very significant fortieth anniversary of the end of the State of
Palestine.  But the hacker included programming errors that caused the virus
to be identified before it could cause damage.

The Israeli virus was able to infect both .COM and .EXE types of executable
programs.  The virus program was intended to seek out .EXE files and check
first if they had already been infected.  It failed to make the check properly
and so kept on reinfecting .EXE files, increasing them in size by over 1800 
bytes on each occassion.  The same mistake was not made with .COM files, but 
still the growth of the .EXE files reached the point where memory just could 
not contain them.  the resultant slowing down and apparent loss of computer
power gave advance warning before the big crash could occur.  

---------------------------------------------------------------------------
"Computer Viruses, Worms, Data Diddlers, Killer Programs, and Other Threats
To Your System: What They Are, How They Work, And How To Defend your PC, Mac,
Or Mainframe."  McAfee, John and Colin Haynes. (C) 1989 by John McAfee and
Colin Haynes.  St. Martin's Press.  p. 97.
