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From: walker@aedc-vax.af.mil (William Walker C60223 x4570)
Newsgroups: comp.virus
Subject: Re: Can such a virus be written ... (PC)
Message-ID: <0006.9106281824.AA04058@ubu.cert.sei.cmu.edu>
Date: 27 Jun 91 20:41:00 GMT
Sender: Virus Discussion List <VIRUS-L@LEHIIBM1>
Lines: 29
Approved: krvw@sei.cmu.edu

Steven van Aardt (vanaards@project4.computer-science.manchester.ac.uk) writes:

> Is it possible to write a PC virus which installs itself whenever
> you place an infected disk in the drive and do a DIR command ?

Lots of people replied:

> Yes.

But A. Padgett Peterson (padgett%tccslr.dnet@mmc.com) replies:

> No ... you cannot BECOME infected in this manner.

Padgett is right.  To infect a PC, viral code must be executed from
the medium on which it is stored.  The DIR command does not execute
any code from the disk or diskette it is viewing, but just displays
the information contained in the sectors of the requested directory or
subdirectory.  Therefore, if you do a DIR of an infected diskette on a
clean PC, there is no way to infect the PC.  Someone else has
mentioned the possibility of renaming a file to contain ANSI.SYS codes
for remapping the keyboard, but this would not be transparent to the
user, as the remaining information (date, time, and size) would be
shifted to the left.

Bill Walker ( WALKER@AEDC-VAX.AF.MIL ) |
OAO Corporation                        | "Non sequitur -- your facts are
Arnold Engineering Development Center  |  un-coordinated."
M.S. 120                               |           -- NOMAD
Arnold Air Force Base, TN  37389-9998  |