CVE-2022-32476 Explained : Impact and Mitigation

An issue was discovered in Insyde InsydeH2O with kernel 5.0 through 5.5. This CVE involves DMA attacks on the AhciBusDxe shared buffer used by SMM and non-SMM code, leading to TOCTOU race-condition issues that could result in corruption of SMRAM and privilege escalation. Learn more about this critical vulnerability below.

Understanding CVE-2022-32476

This section delves into the details of the CVE-2022-32476 vulnerability.

What is CVE-2022-32476?

CVE-2022-32476 entails DMA attacks on the AhciBusDxe shared buffer that can cause TOCTOU race-condition issues, potentially resulting in SMRAM corruption and privilege escalation.

The Impact of CVE-2022-32476

The impact of this CVE is severe as it allows attackers to corrupt SMRAM and elevate their privileges, posing a significant security risk to affected systems.

Technical Details of CVE-2022-32476

In this section, we look at the technical aspects of CVE-2022-32476.

Vulnerability Description

The vulnerability involves DMA attacks on the AhciBusDxe shared buffer, presenting TOCTOU race-condition issues that can lead to SMRAM corruption and privilege escalation.

Affected Systems and Versions

The vulnerability affects systems running Insyde InsydeH2O with kernel versions 5.0 to 5.5, making them susceptible to exploitation.

Exploitation Mechanism

Attackers can exploit this vulnerability by performing DMA attacks on the AhciBusDxe shared buffer, manipulating SMRAM content and escalating their privileges.

Mitigation and Prevention

To prevent exploitation and mitigate the risks associated with CVE-2022-32476, immediate actions and long-term security practices are crucial.

Immediate Steps to Take

Implement IOMMU protection for the ACPI runtime memory used for the command buffer to mitigate this attack. Additionally, copying the firmware block services data to SMRAM before validation can also help prevent exploitation.

Long-Term Security Practices

Adopt secure coding practices, conduct regular security assessments, and stay updated with security patches to enhance the overall security posture of the system.

Patching and Updates

Regularly update the system with the latest firmware and security patches to address vulnerabilities and improve system resilience.