Vulnerability in Xen Package: Control-flow Enforcement Technology (CET-SS)
Summary
CVE-2023-46841: Recent x86 CPUs offer functionality named Control-flow Enforcement Technology (CET). Affects xen versions < 4.16.5-r7. Fixed in 4.16.5-r7. How to fix ↓
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Background
The Xen package is an open-source hypervisor that provides virtualization services for x86 CPUs. It offers functionality called Control-flow Enforcement Technology (CET), which includes a sub-feature known as Shadow Stacks (CET-SS). CET-SS is designed to protect against Return Oriented Programming attacks by using separate stacks for return addresses. These shadow stacks are not writable by normal instructions and are used to check for possible manipulation of return addresses from the traditional stack. However, a missing operation in the interaction between the traditional stack and the shadow stack has led to a vulnerability.
Vulnerability Detail
The vulnerability in Xen's CET-SS implementation allows for potential manipulation of return addresses coming from the traditional stack. This can be exploited by attackers to execute arbitrary code or launch Return Oriented Programming attacks. The issue arises due to the missing counterpart operation for removing a call frame from the shadow stack during recovery. As a result, the integrity of the shadow stack is compromised, undermining the protection provided by CET-SS.
How To Fix
Minimum fixed version
4.16.5-r7
This is the first release that contains the fix.
sudo apk add --upgrade xenTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
There is no known workaround for this vulnerability. It is essential to update the Xen package to the fixed versions mentioned above.
Conclusion
The vulnerability in Xen's CET-SS implementation can be mitigated by updating the package to the fixed versions specified. It is essential to promptly apply the recommended updates to ensure the proper interaction between the traditional stack and the shadow stack, thereby protecting against potential exploitation. For further support on vulnerability remediation, please contact DevNack.com.
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FAQ
Control-flow Enforcement Technology (CET) is a feature available in recent x86 CPUs that provides protection against Return Oriented Programming attacks. It includes sub-features like Shadow Stacks (CET-SS) that help safeguard return addresses.
CET-SS uses separate shadow stacks for return addresses, which are not writable by normal instructions. Upon function returns, the contents of the shadow stack are checked for possible manipulation of return addresses from the traditional stack.
This vulnerability in Xen's CET-SS implementation can allow attackers to manipulate return addresses from the traditional stack, potentially leading to the execution of arbitrary code or the launch of Return Oriented Programming attacks.
No, there are no known workarounds for this vulnerability. It is crucial to update the Xen package to the fixed versions mentioned in the 'how_to_fix' section.
You can find more information about this vulnerability in the CVE-2023-46841 JSON file available at the following source: https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2023-46841.json
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