CVE-2012-3494: Low severity Citrix XenServer vulnerability
setdebugreg allows writes to reserved bits of the DR7 debug control register on x86-64. A malicious guest can cause the host to crash, leading to a DoS. If the vulnerable hypervisor is run on future hardware, the impact of the vulnerability might be widened depending on the future assignment of the currently-reserved debug register bits.
All systems running 64-bit paravirtualised guests are vulnerable to this issue.
Acknowledgements:
Red Hat would like to thank the Xen project for reporting this issue.
Other sources
The setdebugreg hypercall in include/asm-x86/debugreg.h in Xen 4.0, 4.1, and 4.2, and Citrix XenServer 6.0.2 and earlier, when running on x86-64 systems, allows local OS guest users to cause a denial of service (host crash) by writing to the reserved bits of the DR7 debug control register.
Affected Software
Remediation
Patch Available
Event History
Frequently Asked Questions
What is the severity of CVE-2012-3494?
CVE-2012-3494 has been classified as a high severity vulnerability due to its potential to allow unauthorized access to reserved bits in the debug control register.
How do I fix CVE-2012-3494?
To mitigate CVE-2012-3494, it is recommended to update to the latest version of Citrix XenServer or Xen that has addressed this vulnerability.
Which versions are affected by CVE-2012-3494?
CVE-2012-3494 affects Citrix XenServer versions up to and including 6.0.2 and Xen versions 4.0.0, 4.1.0, and 4.2.0.
What type of systems are impacted by CVE-2012-3494?
CVE-2012-3494 impacts x86 and x86-64 architectures running vulnerable versions of Citrix XenServer and Xen.
Is there a workaround for CVE-2012-3494?
There are no specific workarounds for CVE-2012-3494, so upgrading to a patched version is the best course of action.