As we outlined on the Microsoft Security Response Center blog, the update released with Security Advisory 2718704 invalidated unauthorized digital certificates that were used in targeted attacks. In addition to the security advisory, we have also developed a critical update available through Windows Intune to protect customers. Microsoft recommends that customers approve and deploy this critical update as soon as possible. If you are using an auto-approval rule for critical updates, you are already protected and no action is required. For more information, visit the Microsoft Security Response Center’s blog on this issue.