Monthly Archives

June 2012

XenSummit : Quick Update

By | Announcements

I wanted to thank everybody who submitted a proposal to speak for XenSummit. This year we had the most submissions we ever had. The XenSummit PMC will have its first meeting later this week: we are hoping that we will be able to announce the XenSummit program in the first week of July. This may be a tall order though, as we will have togo through a lot of very good proposals.

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The Intel SYSRET privilege escalation

By | Uncategorized

The Xen Security team recently disclosed a vulnerability, Xen Security Advisory 7 (CVE-2012-0217), which would allow guest administrators to escalate to hypervisor-level privileges. The impact is much wider than Xen; many other operating systems seem to have the same vulnerability, including NetBSD, FreeBSD, some versions of Microsoft Windows (including Windows 7), and possibly Apple OSX.
So what was the vulnerability? It has to do with a subtle difference in the way in which Intel processors implement error handling in their version of AMD’s SYSRET instruction. The SYSRET instruction is part of the x86-64 standard defined by AMD. If an operating system is written according to AMD’s spec, but run on Intel hardware, the difference in implementation can be exploited by an attacker to write to arbitrary addresses in the operating system’s memory. This blog will explore the technical details of the vulnerability.

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