Critical Vulnerability in Linux Package: USERGS_SYSRET64 Paravirt Call Issue
Summary
DEBIAN-CVE-2021-4440: In the Linux kernel, the following vulnerability has been resolved: x86/xen: Drop USERGS_SYSRET64 paravirt call commit afd30525a659ac0ae0904f0cb4a2ca75522c3123 upstream. Affects linux versions < 5.10.218-1. Fixed in 5.10.218-1. How to fix ↓
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Background
The Linux package is a core component of the Debian operating system, providing essential functionalities for managing hardware resources and executing processes. It is widely used in various environments, including servers and desktops. The package is known for its stability and performance, but it is also susceptible to vulnerabilities that can compromise system security and efficiency.
Vulnerability Detail
In the Linux kernel, a vulnerability has been identified related to the USERGS_SYSRET64 paravirt call. This issue arises when a Xen PV guest uses the IRET hypercall instead of the intended SYSRET for returning from a syscall. The lack of a sysret PV hypercall leads to complications in stack management, potentially exposing the system to performance degradation and security risks. The vulnerability was introduced in earlier versions and has been addressed in the fixed version 5.10.218-1.
How To Fix
Minimum fixed version
5.10.218-1
This is the first release that contains the fix.
sudo apt-get install --only-upgrade linuxTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Workaround
Currently, there are no specific workarounds mentioned for this vulnerability. The best course of action is to apply the patch by updating the package as described above.
Conclusion
The USERGS_SYSRET64 vulnerability in the Linux package poses significant risks, particularly in Xen PV environments. It is essential to update to the patched version 5.10.218-1 to safeguard your system. Regular monitoring and prompt updates are vital for maintaining system security.
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FAQ
The vulnerability can lead to performance issues and potential security risks in Xen PV environments.
You can use Vulert to monitor and alert for open-source vulnerabilities in your software. Visit Vulert Scanner to check if your application is affected.
Yes, the vulnerability has been patched in version 5.10.218-1 of the Linux package.
While there are no specific workarounds, it is crucial to plan for an update as soon as possible to mitigate risks.
The issue was reported by Brad Spengler and Salvatore Bonaccorso.
References
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