[GTALUG] Intel - secure boot

[R. Russell Reiter]

On March 29, 2015 9:26:07 PM EDT, "D. Hugh Redelmeier" <hugh at mimosa.com> wrote:
>| From: R. Russell Reiter <rreiter91 at gmail.com>
>
>| Here's a link to a talk on secure boot exploits etc. There's a bit on
>
>| exploits which come in over the video aperture in order to flip the
>bits 
>| and get write permission on the secured stack, which I found 
>| interesting.
>
>An interesting video, thanks.
>
>But it is nothing actually to do with video.  It is all to do with the
>many different ways memory addresses get mapped in the x86
>architecture and how each of them can create ways of addressing
>physical resources that need to be protected.
>

Quite right. My poor choice of words describing the content of the video, might lead a reader to assume it relates to a viral type of exploit rather than an embedded feature/bug. Sorry bout that.


>Many protection mechnisms work on limiting address ranges and various
>address mappings, if not carefuly restricted themselves, can evade the
>primary protections.
>
>In the cases he mentioned. System Management Mode code and data is
>protected by some address restriction method.  But if the apperture is
>set to point into the SMM area, certain ops can clobber SMM memory.
>The details are technical and I have not retained them in the few
>hours since I saw it.

I downloaded the presentation. Should make for good TTC fare, if you'll pardon the pun.
>
>This just emphasizes that complexity is the enemy of security.  All
>the systems that they attacked seemed complicated to me. 

I think this is the point of machine learning which, if achieved, may serve to provide the fluidity required to approximate a human concept; common sense. Which I think we all know does not truly exist and yet seems to be a universal requirement of enterprise computing.

>because of how the x86 has evolved as a set of interlocking hacks.
>
>I wonder if we can use the A20 gate to fool some of these checks.  Now
>there is cruft.
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