Re: [RFC] Second attempt at kernel secure boot support

From: Matthew Garrett
Date: Fri Nov 02 2012 - 20:22:40 EST


On Fri, Nov 02, 2012 at 11:38:23PM +0000, James Bottomley wrote:
> On Fri, 2012-11-02 at 18:04 +0000, Matthew Garrett wrote:
> > A user runs a binary that elevates itself to admin. Absent any flaws in
> > Windows (cough), that should be all it can do in a Secure Boot world.
> > But if you can drop a small trusted Linux system in there and use that
> > to boot a compromised Windows kernel, it can make itself persistent.
>
> We seem to be talking past each other. Assume you managed to install a
> Linux boot system on the windows machine. If the linux boot requires
> present user on first boot (either because the key of the bootloader
> isn't in db or because the MOK database isn't initialised), you still
> don't have a compromise because the loader won't start automatically.

Why would an attacker use one of those Linux systems? There's going to
be plenty available that don't have that restriction.

--
Matthew Garrett | mjg59@xxxxxxxxxxxxx
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