AMD is going to patch UEFI SMM callout privilege escalation flaw

AMD is going to release patches for a flaw affecting the System Management Mode (SMM) of the Unified Extensible Firmware Interface (UEFI).

AMD recently announced that it was preparing patches for an SMM Callout Privilege Escalation vulnerability, tracked as CVE-2020-12890, that affects the System Management Mode (SMM) of the Unified Extensible Firmware Interface (UEFI).

The vulnerability was discovered by the security researcher Danny Odler, it resides in the AMD’s Mini PC could allow attackers to manipulate secure firmware and execute arbitrary code.

“AMD is aware of new research related to a potential vulnerability in AMD software technology supplied to motherboard manufacturers for use in their Unified Extensible Firmware Interface (UEFI) infrastructure and plans to complete delivery of updated versions designed to mitigate the issue by the end of June 2020.” reads the AMD’s announcement.

“The targeted attack described in the research requires privileged physical or administrative access to a system based on select AMD notebook or embedded processors. If this level of access is acquired, an attacker could potentially manipulate the AMD Generic Encapsulated Software Architecture (AGESA) to execute arbitrary code undetected by the operating system.”

The issue could be exploited by attackers only if they have privileged physical or administrative access to a system that includes one of the affected AMD notebook or embedded processors.

If these pre-conditions are met, an attacker could potentially manipulate the AMD Generic Encapsulated Software Architecture (AGESA) to execute arbitrary code without being detected by the operating system.

AMD pointed out that only certain processors released between 2016 and 2019 are affected by the vulnerability.

The chip vendor has already delivered most of the updated versions of AGESA to its partners.

AMD recommends users to kept their systems updated by installing the latest patches.

“SMM is the most privileged code that can execute on x86 CPU thus allowing to attack any low level component including Kernel and Hypervisor.” reads the analysis published by Odler.

Odler discovered three vulnerabilities in SMM, the CVE-2020–14032 flaw was addressed in early June, the remain ones are yet to be addressed.

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Pierluigi Paganini

(SecurityAffairs – hacking, chips)

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Pierluigi Paganini

Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.