November's Patch Tuesday brought six updates, four of them critical, starring fixes for Windows 8 and a patch that addresses a highly exploitable vulnerability in IE 9.
Vulnerability management firm Qualys rates the Internet Explorer update (MS12-071) as easily the most urgent. Left unpatched, the set of four flaws easily lend themselves to exploitation through drive-by download style attacks. Microsoft rates its exploitability as "1," which means that it is relatively easy to develop malicious code.
Three vulnerabilities in the Windows kernel, including a critical font-handling module flaw, are tackled by the MS12-075 update. Bugs in the Windows Shell are also on the critical list. Another bulletin, MS12-074, addresses five vulnerabilities in the .NET framework - one of them critical.
But .NET applications are turned off by default, so Qualys argues that a file format vulnerability in Microsoft Excel, which Microsoft rates as "important", might actually be a bigger risk. "We think any vulnerability in a popular application that allows Remote Code Execution should be high on any IT administrator's list to fix," writes Wolfgang Kandek, CTO of Qualys. "Excel 2013, Microsoft's newest version, published just this year, is the only version of Excel not affected. All other versions of Excel should apply this patch."
Windows 8 debuted last month with a number of security improvements. The operating system already needs patching because the infant OS is affected by three of this month's vulnerabilities. It's unclear if any of the three blocks a remote code execution bug which exploit merchants VUPEN bragged about discovering just days after the release.
Andrew Storms, director of security operations at nCircle, characterised needing to patch Windows 8 so soon after its release as about as surprising as having to give a toddler its first round of inoculations.
"Much of the core operating system is reused from version to version, even in new releases, and all software has bugs," Storms said. "These factors, combined with security researchers that love to find and report bugs in the latest software version, are reasons for the number of bulletins for Windows 8. This should surprise no one."
Microsoft's security bulletin notice, which has the full details of the runners and riders in this month's release, can be found here. A more readable patching matrix from the SANS Institute's Internet Storm Centre is here.
The security updates from Microsoft come hot on the heels of patches for Adobe Flash and Apple Quicktime, third-party applications that are frequently targeted for attack using cybercrime tools such as the infamous BlackHole exploit kit. ®