CVE-2023-46837 : Vulnerability Insights and Analysis
Arm cache vulnerability in Xen allows a malicious guest to read sensitive data from memory belonging to other guests. Learn the impact, mitigation, and prevention steps.
Understanding CVE-2023-46837
Arm provides multiple helpers to clean & invalidate the cache for a given region, but an arithmetic overflow in the helpers can lead to skipping cache cleaning, potentially allowing a malicious guest to read sensitive data from another guest's memory. This vulnerability was meant to be addressed by XSA-437, which was not sufficient.
What is CVE-2023-46837?
The vulnerability in Arm's cache cleaning/invalidation helpers can result in unreliable memory writes reaching the memory, potentially leading to data leakage between guests.
The Impact of CVE-2023-46837
A malicious guest exploiting this vulnerability could access sensitive data from memory previously allocated to other guests, posing a risk to data confidentiality.
Technical Details of CVE-2023-46837
Vulnerability Description
The vulnerability stems from an arithmetic overflow in the cache cleaning/invalidation helpers provided by Arm, resulting in unreliable memory writes.
Affected Systems and Versions
All versions of Xen are affected by this vulnerability. However, only systems running Xen on Arm 32-bit architecture are vulnerable.
Exploitation Mechanism
Exploiting this vulnerability allows a malicious guest to potentially read sensitive data from memory allocated to other guests due to unreliable cache cleaning.
Mitigation and Prevention
Immediate Steps to Take
At present, there is no known mitigation available for CVE-2023-46837. System administrators are advised to monitor for any updates or patches provided by Xen or Arm.
Long-Term Security Practices
To enhance security, organizations should regularly monitor security advisories from Xen and Arm, apply updates promptly, and follow security best practices for virtualized environments.
Patching and Updates
Users are recommended to follow the guidance provided in Xen's advisory XSA-447 to address the vulnerability. Ensure that systems running Xen on Arm 32-bit are updated with the necessary patches to mitigate the risk of data leakage.