Xen - Security Update
Summary
DLA-720-1: xen - security update. Affects xen versions < 4.1.6.lts1-4. Fixed in 4.1.6.lts1-4. How to fix ↓
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Background
Xen is a hypervisor that provides virtualization services for x86-compatible computers. It allows multiple operating systems to run concurrently on a single physical machine. Xen is widely used in cloud computing platforms and virtual private server hosting. However, several vulnerabilities have been discovered in Xen that could potentially be exploited by malicious actors to gain unauthorized access or escalate privileges.
Vulnerability Detail
The Xen hypervisor is affected by multiple vulnerabilities:
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CVE-2016-9379 / CVE-2016-9380 (XSA-198): The pygrub boot loader emulator fails to properly quote or validate its results, allowing a malicious guest administrator to access sensitive host files.
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CVE-2016-9381 (XSA-197): The compiler used by Xen can introduce optimizations in qemu that may lead to double fetch vulnerabilities. This can be exploited by malicious administrators to take over the qemu process and elevate its privileges.
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CVE-2016-9382 (XSA-192): The LDTR loading in Xen does not follow protected mode semantics, allowing a malicious unprivileged guest process to crash the system or escalate its privileges.
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CVE-2016-9383 (XSA-195): Xen's internal recalculation of memory addresses and register operands can discard high bits, resulting in incorrect memory locations and register operands. A malicious guest can exploit this to modify arbitrary memory.
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CVE-2016-9386 (XSA-191): The Xen x86 emulator fails to consider the unusability of segments during memory accesses, potentially allowing an unprivileged guest user program to elevate its privileges to that of the guest operating system.
How To Fix
Minimum fixed version
4.1.6.lts1-4
This is the first release that contains the fix.
sudo apt-get install --only-upgrade xenTip — Not sure which version your app runs? Vulert can match this fix to it. Scan free →
Conclusion
Multiple vulnerabilities have been discovered in the Xen hypervisor. It is crucial to upgrade the Xen packages to the latest version to mitigate the risks associated with these vulnerabilities. Regularly updating Xen is essential to ensure the security of your virtualized environment. For further support on vulnerability remediation, you can contact DevNack.com.
See every vulnerability recorded for xen →
FAQ
Xen is a hypervisor that allows multiple operating systems to run concurrently on a single physical machine. It is widely used in cloud computing platforms and virtual private server hosting.
There are multiple vulnerabilities in Xen, including pygrub failing to properly quote or validate its results, compiler optimizations leading to double fetch vulnerabilities, LDTR loading not following protected mode semantics, incorrect memory locations and register operands, and failure to consider segment unusability during memory accesses.
These vulnerabilities could allow malicious actors to access sensitive host files, take over the qemu process, crash the system, escalate privileges, modify arbitrary memory, or elevate guest user program privileges.
To fix these vulnerabilities, it is recommended to upgrade the Xen packages to the latest version. For Debian 7 Wheezy, the fix is available in version 4.1.6.lts1-4. For Debian 8 Jessie, the fix will be released shortly.
It is important to regularly update the Xen hypervisor to ensure the latest security patches are applied. Check for updates and apply them as soon as they become available.
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