[comp.virus] Viruses in Data Files

WHMurray@DOCKMASTER.NCSC.MIL (04/06/90)

>There is NO evidence that anything other than an .exe, .com, .ovl, or
>.sys file can infect.  There has been talk about .pgm files (for
>dBase) and lotus spreadsheets being carriers but I have no evidence of
>any known.

"Not so, Mr. Schuyler!"

That is a very large NO, and I do not wish to get into a shouting match
with my learned colleague.  Neither do I wish for the rest of you to be
mislead.

First, I think that my colleague speaks in the very narrow sense of
MS-DOS.  While this is the important territory for the moment, it is not
all there is.

Ken Thompson, in his Turing Award acceptance, describes a very credible
scenario of a virus in source code.  He makes the relevant point.  "One
man's data is another man's program."

There is very credible evidence that a 1-2-3 .wks file, which looks for
all the world like a data file, can contain a macro which will create a
copy of itself in all .wks files such that use of those will cause
further copies.  That sounds like a virus to me.

It is not clear that such a .wks file could achieve the feat of
infecting .exe or .com files.  And it is clear that it can only execute
in a 1-2-3 environment.  It cannot operate in a DOS, UNIX, or primitive
hardware environment.  But that was a BIG no, we do not wish to mislead,
One man's data is another's program, and not everyone operates in a DOS
only environment.

My point is that anyone can tell a lie a in any language.  Whenever you
accept ANY data from another, you run some risk of being duped.  While
it is true that the virus writer must solve the problem of getting his
program in control, and that that problem is more easily solved in some
environments than in others, do not under-estimate the ingenuity of the
malicious.

While the current battle is being waged on the PC battlefield, and while the
war may even be won or lost here, the phenomenon should be known in the
broadest and most general light.

William Hugh Murray
21 Locust Avenue, Suite 2D, New Canaan, Connecticut 06840