From: RADAI@vms.huji.ac.il (Y. Radai)
Newsgroups: comp.virus
Subject: Re: Good use of (possible bad) viruses
Date: 7 Jan 93 15:37:53 GMT


  Suzana S.-C. [sorry, I can't cope with such a long name] writes:

> Just one of those days...Two examples of good use of (possible bad)
> viruses come to my mind :
>
> 1. Viruses written to improve an A-V product
>
> The logic is simple. It is better that I write virus which can do this
> or that and have prepared solution to implement in my A-V product than
> wait that such virus arises in wild and then react. That means if I
> know that today exist viruses which could be stealthy, tunneling or
> polymorfic why shouldn't I write virus which is all that and design my
> A-V product to recognize such virus before it really appears in wild.
> (Well, maybe it is not commercial, I don't know). If such virus *by
> accident* escape from my lab I already have a response and there is no
> ethical problem at all.

You definitely should try to anticipate new types of viruses.  But
why do you have to *write a virus* to do this?  It's certainly
pointless in the case of scanners, and in the case of other types of
AV software, it's usually sufficient to *think* of what a new type of
virus might do, and to modify your AV product accordingly, without
actually writing such a virus.  (And if your virus does escape by
accident, it would suggest irresponsibility on your part, so I think
you *would* have an ethical problem.)

  (Btw, although this evidently was not what you were referring to,
it reminds me of a few cases I have heard of in which the authors of
a known-virus scanner have written a new virus and inserted a corres-
ponding pattern into their scanner, so that the virus is detectable
by their scanner but not by their competitors' scanners.  They then
adduce this as "proof" that their product is better than those of
their competitors.  Needless to say, this would be highly unethical
in the opinion of most people.)

> 2. Viruses built in an A-V product (it's just an idea, don't blame me if it
> is not applicable in reality)
>
> Suppose that we have an A-V product which in regular intervals or
> randomly send a virus in system. Virus (fast infector) infects only
> programs which checksum doesn't correspond to previously calculated
> values. If no such program is found virus deletes itself or removes
> from memory. If changed program found virus activates scanner to check
> if there is any known virus.  If known virus is found message is sent
> to the user. If program is changed and no known virus is found the
> message is sent to the user to make decision.  If decision is to leave
> program as is, virus cuts itself from the program.  The whole process
> (except messages) takes place in background. There is no need for all
> A-V program (which is combination of I-checker and scanner) to be TSR,
> only virus is occasionally TSR. There is slight similarity in this
> idea with reaction of human immunity system. Anyone has ethical
> problem with her/his own immunity system ?

I'm afraid I don't understand this one at all.  What's the advantage
of infecting files?  Just so that the I-checker and scanner don't have
to be resident?  There are lots of I-checkers and scanners which are
*non-resident*.  Not only does that save memory, but it's also a more
secure way of doing things.  The advantage of your proposal seems to
me completely outweighed by the risks involved.

                                     Y. Radai
                                     Hebrew Univ. of Jerusalem, Israel
                                     RADAI@HUJIVMS.BITNET
                                     RADAI@VMS.HUJI.AC.IL