On August 13th, Microsoft released a security advisory update (2862973 – Update for Deprecation of MD5 Hashing Algorithm for Microsoft Root Certificate Program), applicable to Windows Vista/2008 and later client and server operating systems. According to the associated TechNet article (Protecting Against Weak Cryptographic Algorithms) the functionality is already built into Windows Server 2012R2 and Windows 8.1 preview editions and should be included when the final bits of 2012R2 and 8.1 ship. Essentially, this update gives administrators control on logging and/or blocking weak algorithm-based certificates that are known to be vulnerable to multiple attacks. More detailed information can be found on the link above.