oss-sec mailing list archives

Re: CVE-2023-23583: Intel - Denial of Service - Privilege Escalation (Reptar)


From: Demi Marie Obenour <demi () invisiblethingslab com>
Date: Tue, 14 Nov 2023 13:58:21 -0500

On Tue, Nov 14, 2023 at 10:31:51AM -0800, Antonio Gomez Iglesias wrote:
Name of the issue: Redundant Prefix Issue


Description of the issue
Under certain microarchitectural conditions, Intel has identified cases
where execution of an instruction (REP MOVSB) encoded with a redundant
REX prefix may result in unpredictable system behavior resulting in a
system crash/hang, or, in some limited scenarios, may allow escalation
of privilege from CPL3 to CPL0.
This Redundant Prefix Issue is assigned CVE-2023-23583 with a CVSS Base
Score of 8.8 High CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.


Mitigation
Intel is providing a microcode update to mitigate this issue: 
https://github.com/intel/Intel-Linux-Processor-Microcode-Data-Files/releases/tag/microcode-20231114

Does this also allow privilege escalation from a VM guest to the host?
What are the limited scenarios?
-- 
Sincerely,
Demi Marie Obenour (she/her/hers)
Invisible Things Lab

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