nanog mailing list archives

Re: Potentially dangerous Pentium bug disc


From: Michael McArthur <mcarthur () ans net>
Date: Wed, 12 Nov 1997 10:42:30 -0500 (EST)

On Tue, 11 Nov 1997, Jay R. Ashworth wrote:

Date: 09 Nov 1997 09:26:39 +0100
From: Torsten Hilbrich <Torsten.Hilbrich () bln de>
Subject: New Pentium flaw

Yesterday (Nov, 8) I found the following information on the news-ticker
page of the German Heise-Verlag (shortened to the essential information):

The Pentium in standard and MMX version halts on execution of the
instruction:
   F0 0F C7 C8
This code sequence works independent of any memory protection of the
operating system.

I was able to reproduce this bug on a Pentium 133 system with the following
operating systems: DOS, Windows 95, Linux 2.0.31, and FreeBSD 2.2.x.

I don't know about PentiumPro and Pentium II.

The risk?  Every pentium based server with user access for executing
programs can be crashed using this code sequence.  Not to mention Trojan
Horses or Active-X controls.



        Does anybody know if this affects the Cyrix and AMD "Pentium
Clone" chips?





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