Saturday, November 28, 2009

Virtualization security and the Intel privilege model

Earlier this month, Tavis and I spoke at PacSec 2009 in Tokyo about virtualisation security on Intel architectures, with a focus on CPU virtualisation.

During this talk, we briefly explained various techniques used for CPU virtualisation such as dynamic translation (QEmu), VMware-style binary translation or paravirtualisation (Xen) and we went through bugs found by us and others:

- We released some details about MS09-33 (CVE-2009-1542), a bug we found in VirtualPC's instructions decoding
- We mentioned two of the awesome bugs found by Derek Soeder in VMware, CVE-2008-4915 and CVE-2008-4279
- We explained and demo-ed the exploitation of the mishandled exception on page fault bug in VMware that I previously blogged about.
- We released information on CVE-2009-3827, a bug we discovered in Virtual PC's hardware virtualisation.
A funny fact is that the exact same bug was independently uncovered and corrected in KVM later by Avi Kivity (CVE-2009-3722). The reason may be a not perfectly clear Intel documentation about the differences between MOV_DR and MOV_CR events in hardware virtualisation.
This bug has already been addressed by Microsoft in Windows 7 and will get corrected in the next service pack for Virtual PC and Virtual Server.

If you are interested, you can download the slides here.

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