Patch Tuesday December 2011

Microsoft finishes out this year of patching with a heavy release that’s all over place. While techs were notified of an anticipated 14 bulletins, 13 were released for the month of December. Headline grabbing events and code are addressed in one of them, and while fewer are labelled “Critical”, are they any less important?

Many speculative bits have been spilled on the group behind Stuxnet and its precursor Duqu, with our own researchers posting at least a half dozen Securelist writeups on Duqu findings alone. MS11-087 patches up the delivery vector for Duqu itself. This kernel mode vulnerability was publicly identified and confirmed at the beginning of November, but could well have been used quietly in attacks around the world for a year or more.

The targeted functionality provides TrueType font parsing capabilities for the OS, and the group abused these components by delivering exploits in the form of Word Documents attached to emails interesting to their individual victims, a technique known as spear-phishing. The flawed code has been known to impact only a very select set of systems throughout the world.

The other headline grabbing event and code that was anticipated to be released is known as the SSL BEAST vulnerability. We covered the potential hysteria surrounding the Ekoparty conference demo in Argentina a couple of months ago, where a researcher demonstrated SSL being cracked on a Windows system. There were no public reports whatsoever of this flaw being attacked, and Microsoft is delaying its release to ensure that its browser cannot be hacked in this way without compatibility issues, following the lead of Google Chrome and Firefox.

A slew of other patches were released this time around, with Internet Explorer, Powerpoint, and other components, including the Chinese font producing Pinyin IME component, all being updated. It’s interesting that even Microsoft considers exploit code likely to be published for at least a dozen of them, but does not consider many of them critical for admins to patch. One that stands out as a candidate for “Critical” in my book is the Active Directory problem. Organizations that have been under persistent targeted attacks may consider this one to be very urgent, with Domain Controllers and Active Directory of high interest to their adversaries in past attacks.