Messages in this thread | | | Date | Thu, 4 Mar 1999 00:57:27 +0100 | From | Vojtech Pavlik <> | Subject | Re: P-III serial number security in Linux |
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On Wed, Mar 03, 1999 at 11:49:07PM +0000, Philipp Rumpf wrote:
> > The serial number, although proven by c't to be possible to switch on > > without rebooting the machine (using a powermanagement trick), is not > > Processor reset, AFAIK. Not Power Management. You set the CMOS shutdown state > byte, ask the keyboard controller to reset (or have a triple-fault) and come > back to life. As Intel's proposal at that time was to switch off the PSN after > the system booted, it would not have been disabled. The current way is to dis- > able it in the BIOS, which will work.
Well, I can only base on what I've heard. The approach you describe above will certainly work, but I have read somewhere that putting the CPU into off mode for a short moment through power management worked too, somehow.
> > Intel's serial number disabling utility 'fixes' this security hole (or > > backdoor?) by disabling the serial number feature repeatedly every 15 > > seconds. > > Oh. New to me. AFAIK, they only said it to be disabled by the BIOS.
Hmm, I think I'll have to dig the article out somewhere. I think the BIOS way is 'fix #2' when they realized the first won't work.
> Nope, you have to change the bit in the NVRAM that says the PSN is to be > disabled. No problem though if you know what mobo you're running on.
Yeah, both the Awards and AMIs (which are the most common) have a NVRAM layout description in the FlashROMs, all with bit fields and menu item texts. Piece of cake to find the right bit in this case.
Have fun, Vojtech
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