CVE-2012-3494

Name of the Vulnerable Software and Affected Versions Xen versions 4.0 through 4.2 Citrix XenServer version 6.0.2 and earlier

Description The issue allows local OS guest users to cause a denial of service by writing to the reserved bits of the DR7 debug control register. This is possible through the set debugreg hypercall in include/asm-x86/debugreg.h when running on x86-64 systems.

Recommendations For Xen versions 4.0 through 4.2, consider restricting access to the set debugreg hypercall to prevent local OS guest users from causing a denial of service. For Citrix XenServer version 6.0.2 and earlier, restrict access to the set debugreg hypercall in include/asm-x86/debugreg.h to minimize the risk of exploitation.