Microsoft patches critical vulnerabilities, secures IE

At first take, it looked like Microsoft would continue the 2014 trend of keeping patch Tuesday relatively light. There were only 5 advisories this month, two critical, three important. Emphasis is on the past tense.

Yesterday morning, Microsoft updated the advance notification to add two more bulletins. Basically, they added an IE patch and an OS patch, both marked Critical, Remote Code Execution. In eight years of dissecting these announcements, I don’t recall them ever adding to the advance notification between its release and the Tuesday of the patches.

I talked this over with some folks in the know, and the message is that something (in the IE patch) came in just under the wire, in terms of testing completeness on Microsoft’s side. Due to the criticality of it, they bent their schedule in favor of customer security to get the patch out sooner.

The added OS patch is a variant of one of the IE patches, and shares a CVE. Reaction to this could fall into one of two camps, either fear that something is being rushed out the door, or relief that we don’t have to wait another month for an IE roll-up, which is a really long time on the internet.

The two critical advisories in the original bulletin were unusual in that they don’t touch older versions of Windows or Internet Explorer. The first (MS14-007) patches a remote code execution vulnerability that affects Windows 7 through to Windows 8.1, including 8.1 RT. The second (MS14-008), also remote code execution, is actually an issue in Forefront Protection for Exchange Server (2010).

Given a remote code execution in a perimeter service like Forefront, I’d be inclined to say that this would be the highest priority patching issue this month. However, there is apparently no known exploitation of this in the wild, no known exploit vector, and this was found internally by Microsoft in a code analysis. So I’m going to call the IE 24 CVE rollup, MS14-010, the highest priority for patching. The second priority is, not surprisingly, the critical in Windows 7 and later issue (MS14-007), the third is the OS variant of the one CVE in that also affects IE, MS14-011.

The other three issues are all of lower risk and likely lower exploitability, ranging from information disclosure to denial of service and elevation of privilege. Not to be ignored, but should be of slightly less concern than remote critical vulnerabilities.

Author: Ross Barrett, Senior Manager, Security Engineering, Rapid7.