Microsoft Update Product Team Blog
6 Jun 2012
As part of the phased mitigation strategy we outlined on the MSRC blog, an update was released with Security Advisory 2718704 that prevents unauthorized certificates from being used to attack Windows systems. In an effort to provide additional protection for customers, the next action in our mitigation strategy is to further harden Windows Update as a defense-in-depth precaution. Now that we have seen broad adoption of Security Advisory 2718704, our deployment of the security hardening update to Windows Update and Windows Server Update Services (WSUS) infrastructures will begin to roll out over the next few days.
Our hardening introduces two defense-in-depth changes. First, we have further hardened the Windows Update infrastructure so that the Windows Update client will only trust files signed by a new certificate that is used solely to protect updates to the Windows Update client. Second, we are strengthening the communication channel used by Windows Update in a similar way. WSUS customers will also receive an update; more details will be found on the Knowledge Base when the update becomes available.