Path: utzoo!attcan!uunet!lll-winken!ames!pasteur!ucbvax!pro-freedom.cts.com!cdm
From: cdm@pro-freedom.cts.com (Carl Macdonald)
Newsgroups: comp.sys.apple
Subject: Viruses
Message-ID: <8903021638.AA26153@crash.cts.com>
Date: 26 Feb 89 00:16:08 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Reply-To: pnet01!pro-ascii!pro-newfrontier!pro-freedom!cdm@nosc.mil
Organization: The Internet
Lines: 32

I've noticed a lot of talk on the net lately about viruses and concern over
suppressing information about how they work.  This is a very ligitamate
concern, however, a virus program is one of the easiest pieceses of software
to write, and really doesn't involve much sophistication.

When I was in college (Many years ago), we were doing research on how fast
viruses spread and what could be done to stop them in a mini-computer
environment. We discovered two things, 1) It was very easy to create a virus,
and was usually a very small piece of code, and 2) It was very difficult to
stop them.

The most prommissing line of prevention we found was to make frequent backups
that went back at least a month. Then we had a program that would install a
small piece of code at the top of likely target files (Program files). This
piece of code would perform a checksum on the file at load time and compare it
to the checksum that was performed when it was installed. If they didn't match
it would signal a detection and stop the program.  Then it was a matter of
loading from the backups.

Carl MacDonald, programmer
Central Point Software

DISCLAIMER: All opinions expressed here are my own, not those of my employer
            or anyone else, living or otherwise.
 
    UUCP: crash!pnet01!pro-freedom!cdm
 ProLine: cdm@pro-freedom
 ARPANet: crash!pnet01!pro-freedom!cdm@nosc.mil
InterNet: cdm@pro-freedom.cts.com

Programmer: Red-eyed mumbling mammal capable of conversing with in-animate    
            objects.