CVE-2023-20528 : Security Advisory and Response

This CVE record was published by AMD on January 10, 2023. It pertains to a vulnerability with insufficient input validation in the System Management Unit (SMU) that could allow a physical attacker to exfiltrate SMU memory contents over the I2C bus, potentially resulting in a loss of confidentiality.

Understanding CVE-2023-20528

This section will provide an overview of what CVE-2023-20528 is about, its impact, technical details, and mitigation steps.

What is CVE-2023-20528?

The CVE-2023-20528 vulnerability involves insufficient input validation in the SMU, which could be exploited by a physical attacker to extract SMU memory contents via the I2C bus, leading to a potential breach of confidentiality.

The Impact of CVE-2023-20528

The impact of this vulnerability is significant as it allows a malicious actor physical access to the system to retrieve sensitive SMU memory contents, potentially compromising the confidentiality of the data stored within.

Technical Details of CVE-2023-20528

In this section, we will delve into the vulnerability description, affected systems and versions, as well as the exploitation mechanism.

Vulnerability Description

The vulnerability lies in the inadequate input validation in the SMU, enabling a physical attacker to access and retrieve SMU memory contents over the I2C bus, posing a risk to data confidentiality.

Affected Systems and Versions

The CVE-2023-20528 affects certain versions of the AGESA firmware on the 2nd Gen EPYC and 3rd Gen EPYC platforms for x86 architecture.

Exploitation Mechanism

An attacker with physical access to the system can exploit the lack of input validation in the SMU to extract sensitive memory contents via the I2C bus, potentially leading to data compromise.

Mitigation and Prevention

This section focuses on the necessary steps to mitigate the CVE-2023-20528 vulnerability and prevent potential security risks.

Immediate Steps to Take

AMD advises users to refer to the provided advisory (AMD-SB-1032) to understand the impact of the vulnerability and implement appropriate security measures.
System administrators are recommended to monitor and restrict physical access to the SMU components to mitigate the risk of exfiltration.

Long-Term Security Practices

Regular security assessments and audits should be conducted to identify and address vulnerabilities in the SMU and associated components.
Implementing robust access controls and encryption mechanisms can help safeguard sensitive memory contents from unauthorized access.

Patching and Updates

It is crucial for users to apply patches or firmware updates provided by AMD to address the insufficient input validation issue in the SMU and enhance system security.
Keeping systems up to date with the latest security patches is essential to mitigate the risk posed by CVE-2023-20528 and similar vulnerabilities.