Bug 2181334 (AMD-SN-4003, CVE-2023-20555)

Summary:	CVE-2023-20555 hw: AMD: SMM Memory Corruption Vulnerability
Product:	[Other] Security Response	Reporter:	Rohit Keshri <rkeshri>
Component:	vulnerability	Assignee:	Nobody <nobody>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	acaringi, allarkin, bhu, chwhite, crwood, dbohanno, ddepaula, debarbos, dvlasenk, ezulian, hkrzesin, jarod, jdenham, jfaracco, jferlan, jforbes, jlelli, joe.lawrence, jshortt, jstancek, jwyatt, kcarcia, ldoskova, lgoncalv, lzampier, nmurray, ptalbert, qzhao, rrobaina, rvrbovsk, rysulliv, scweaver, security-response-team, tglozar, tyberry, walters, wcosta, williams, wmealing, ycote
Target Milestone:	---	Keywords:	Security
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Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in hw. Insufficient input validation in CpmDisplayFeatureSmm may allow an attacker to corrupt SMM memory by overwriting an arbitrary bit in an attacker-controlled pointer, potentially leading to arbitrary code execution in SMM.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
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Bug Blocks:	2180682

Description Rohit Keshri 2023-03-23 17:49:44 UTC

The Binarly efiXplorer team made AMD aware of a potential vulnerability in a display feature component in Client products (CpmDisplayFeatureSMM) where an attacker can rewrite a controlled pointer to point to SMRAM resulting in a one bit overwrite of SMRAM.

Although this vulnerability could have high impact if exploited, AMD believes an attacker may have difficulty carrying out a meaningful attack since the vulnerability allows an attacker to manipulate only a single bit value in SMRAM.

Reference:
https://www.amd.com/en/corporate/product-security/bulletin/amd-sb-4003