Critical Vulnerability in amd64-microcode: IOMMU Address Range Handling Flaw
Summary
UBUNTU-CVE-2023-20584: IOMMU improperly handles certain special address ranges with invalid device table entries (DTEs), which may allow an attacker with privileges and a compromised Hypervisor to induce DTE faults to bypass RMP checks in SEV-... Affects amd64-microcode versions < 3.20250311.1ubuntu0.24.04.1. Fixed in 3.20250311.1ubuntu0.24.04.1. How to fix ↓
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Background
The amd64-microcode package is essential for the proper functioning of AMD processors, providing updates and fixes to the processor's microcode. This package is crucial for maintaining system stability and performance, especially in environments utilizing virtualization technologies. However, it has been identified that certain address ranges are improperly handled, leading to potential security risks.
Vulnerability Detail
The vulnerability, identified as CVE-2023-20584, arises from the IOMMU's improper handling of specific address ranges that contain invalid device table entries (DTEs). This flaw can be exploited by an attacker with sufficient privileges and a compromised Hypervisor, allowing them to induce DTE faults that bypass RMP checks in SEV-SNP. The consequences of this vulnerability include a significant risk to guest integrity, potentially allowing unauthorized access or manipulation of guest systems.
How To Fix
Minimum fixed version
3.20250311.1ubuntu0.24.04.1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade amd64-microcodeTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, no specific workarounds have been provided for this vulnerability. It is advisable to apply the patch as soon as it becomes available to mitigate risks.
Conclusion
The amd64-microcode package has a critical vulnerability that can be exploited to compromise guest integrity. It is essential to update to the patched version to mitigate this risk. Regular monitoring of vulnerabilities using tools like Vulert can help maintain system security.
See every vulnerability recorded for amd64-microcode →
FAQ
CVE-2023-20584 is a vulnerability in the amd64-microcode package that allows attackers to bypass security checks, potentially compromising guest integrity.
You can use the Vulert playground at Vulert Scanner to check if your application is affected by this vulnerability without needing to sign up.
The vulnerability could allow an attacker to gain unauthorized access to guest systems, leading to data breaches or system manipulation.
Yes, a patch is available in version 3.20250311.1ubuntu0.24.04.1 of the amd64-microcode package.
The CVSS score for CVE-2023-20584 is 5.3, indicating a medium severity level.
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