CVE-2021-46794 : Exploit Details and Defense Strategies

CVE-2021-46794 is a vulnerability in AMD Secure Processor (ASP) that could result in a denial of service due to insufficient bounds checking in the System Management Interface (SMI) mailbox checksum calculation.

Understanding CVE-2021-46794

This section provides an overview of the vulnerability.

What is CVE-2021-46794?

Insufficient bounds checking in AMD Secure Processor (ASP) may lead to an out-of-bounds read in SMI mailbox checksum calculation, triggering a potential denial of service.

The Impact of CVE-2021-46794

The vulnerability could result in a denial of service due to an out-of-bounds read, potentially affecting the system's stability and reliability.

Technical Details of CVE-2021-46794

This section delves into the technical aspects of the vulnerability.

Vulnerability Description

The vulnerability involves insufficient bounds checking in ASP, leading to an out-of-bounds read in the SMI mailbox checksum calculation, which can trigger a data abort.

Affected Systems and Versions

Ryzen™ 2000 series Desktop Processors “Raven Ridge” AM4
Ryzen™ 3000 Series Desktop Processors “Matisse” AM4
AMD Ryzen™ 5000 Series Desktop Processors “Vermeer” AM4
Ryzen™ 5000 Series Desktop processor with Radeon™ Graphics “Cezanne” AM4
3rd Gen AMD Ryzen™ Threadripper™ Processors “Castle Peak” HEDT
Ryzen™ Threadripper™ PRO Processors “Castle Peak” WS
Ryzen™ Threadripper™ PRO Processors “Chagall” WS
Athlon™ 3000 Series Mobile Processors with Radeon™ Graphics “Dali”/“Dali” ULP
Athlon™ 3000 Series Mobile Processors with Radeon™ Graphics “Pollock”
Ryzen™ 2000 Series Mobile Processors “Raven Ridge” FP5
Ryzen™ 3000 Series Mobile processor, 2nd Gen AMD Ryzen™ Mobile Processors with Radeon™ Graphics “Picasso”
Ryzen™ 3000 Series Mobile Processors with Radeon™ Graphics “Renoir”
Ryzen™ 5000 Series Mobile Processors with Radeon™ Graphics “Lucienne”
Ryzen™ 5000 Series Mobile processors with Radeon™ Graphics “Cezanne”

Exploitation Mechanism

The vulnerability can be exploited by triggering an out-of-bounds read in the SMI mailbox checksum calculation, leading to a data abort and potential denial of service.

Mitigation and Prevention

This section outlines steps to mitigate and prevent the vulnerability.

Immediate Steps to Take

Monitor vendor communications for patches and updates
Follow best security practices to protect against potential exploitation
Consider implementing additional security measures to safeguard affected systems

Long-Term Security Practices

Regularly update systems with the latest security patches
Conduct thorough security assessments to identify and address vulnerabilities
Implement proper access control measures and network segmentation to reduce attack surface

Patching and Updates

Stay informed about patches and updates released by AMD to address the vulnerability and apply them promptly.