oss-sec mailing list archives

Re: Secure Boot bypass in EDK2 based Virtual Machine firmware


From: Mate Kukri <mate.kukri () canonical com>
Date: Wed, 14 Feb 2024 15:56:15 +0000

In the case of these OVMF/AAVMF images I believe the only other
built-in application accessible is the firmware setup utility and boot
selector.
These obviously provide many capabilities, but require a user present
at the console to access, and to the best of my knowledge not
vulnerable to this attack.
For firmware images provided by other vendors or distributors, I have no idea.

On Wed, Feb 14, 2024 at 3:52 PM Yves-Alexis Perez <corsac () debian org> wrote:

On Wed, Feb 14, 2024 at 03:47:23PM +0000, Mate Kukri wrote:
That is correct in the general case, but here the issue comes from the
fact that a copy of the Shell was included in the firmware image
itself, and as a built-in application was implicitly trusted.

Ah, thanks for the clarification, I didn't know about the implicit trust
on "built-in applications". Out of curiosity, are there other such
applications, which could be abused?

Regards,
--
Yves-Alexis Perez


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