Re: Xen Security Notice 2 (CVE-2024-35347) AMD CPU Microcode Signature Verification Vulnerability

[Solar Designer <solar () openwall com>]

On Sat, Mar 08, 2025 at 01:28:07AM +0000, Andrew Cooper wrote:
> On 06/03/2025 4:48 am, Solar Designer wrote:
> > On Thu, Mar 06, 2025 at 04:11:25AM +0000, Andrew Cooper wrote:
> > > This issue wins points for spite, because the highest risk users are the
> > > ones who were taking proactive steps to try and improve their security,
> > > betting that AMD's patchloader crypto was sound.
> > OK, so this is to protect legitimate sysadmins from loading malicious
> > microcode inadvertently or via a supply chain attack.  Makes sense.
>
> Sorry for the delay, I knew there was a distro formally doing this, but
> I'd lost track of the links.
>
> https://github.com/divestedcg/real-ucode which is packaged for Arch as
> https://aur.archlinux.org/packages/amd-real-ucode-git (and an equivalent
> Intel package).

Thank you for these followup postings, Andrew!  They're very helpful.

I have one late nitpick to add - as jericho @attritionorg pointed out on
Twitter, the Subject line here gives an incorrect CVE number.  The
correct one is CVE-2024-36347.

Alexander