Bugtraq mailing list archives
Re: Intel Pentium Bug
From: I.McWilliam () ST NEPEAN UWS EDU AU (Ian McWilliam)
Date: Sat, 8 Nov 1997 23:13:59 +1100
On Fri, 7 Nov 1997, Aleph One wrote:
On Sat, 8 Nov 1997, Daniele Orlandi wrote:If the CPU microcode is really updateable, it's realistic to think that: 1- Upload requires to be done only when running in ring-0, just like all the other protected instructions. No user program will be able to use this feature.As you (and Eric) point out this is correct. But at the time we where thinking Windows 95 viruses so running in ring-0 is not an issue. Of curse under Unix you should have to subvert the root account and from there install something like a loadable module (similarly under NT). But it happens all to often.
From my info on the pentium cpu's, mainly the P6, the upgradable
microcode is a "segment of bios code provided by INTEL to fix processor bugs. Each different processor has different microcode and it is intergrated into the bios INT15 function call." There is publically available a utility (I have a copy of micode.exe) to check the microcode in the bios and update it as needed. I think that the function of upgrading the microcode is mainly intended for BIOS manufacturers. At worse the BIOS of the motherboard not the cpu is likely to be the target, but with the advent of flash BIOS updates that can be done from DOS with out setting jumpers on the motherboard aka aopen AP5T ver 3.X, this should scare you more than replacing the microcode. ------------------------------------------------------ Ian McWilliam Technical Officer Department of Computing. Faculty of Science & Technology. University of Western Sydney, Nepean. Phone: (047) 360757 Fax: (047) 360 770 Mailto:i.mcwilliam () st nepean uws edu au ------------------------------------------------------
Current thread:
- Re: Intel Pentium Bug Daniele Orlandi (Nov 07)
- Re: Intel Pentium Bug Aleph One (Nov 07)
- Re: Intel Pentium Bug Ian McWilliam (Nov 08)
- <Possible follow-ups>
- Re: Intel Pentium Bug John Pettitt (Nov 07)
- Sidenote of Pentium Bugs Dave (Nov 07)
- Security bug in iCat Suite version 3.0 Mikael Johansson (Nov 08)
- Re: Intel Pentium Bug JoelKatz (Nov 07)
- Re: Intel Pentium Bug Joe Ilacqua (Nov 07)
- Re: Intel Pentium Bug Rubens Kuhl Jr. (Nov 07)
- Re: Intel Pentium Bug Ralf Baechle (Nov 10)
- Re: Intel Pentium Bug Barry Irwin (Nov 08)
- Re: Intel Pentium Bug Bjorn Wesen (Nov 08)
- Re: Intel Pentium Bug Peter Bierman (Nov 08)
(Thread continues...)
- Re: Intel Pentium Bug Aleph One (Nov 07)