After testing IIS Crypto 2.0 we ran into an issue with soon to be released Windows Server 2016. All of the Qualys SSL scans were not recognizing the order of the cipher suites configured by IIS Crypto. It turns out that Microsoft quietly renamed most of their cipher suites dropping the curve (_P521, _P384, _P256) from them. This reduced most suites from three down to one. However, this threw us a bit of a curve ball as now IIS Crypto’s configuration and all of the templates needed to support OS version checking. We added this in one of the beta versions, retested and sure enough the scans were now showing the correct cipher suite order.
While testing the latest version of IIS Crypto, we researched all of the cipher suites for each operating system. Unfortunately there is little up-to-date documentation on the default cipher suites included or their order for TLS negotiation. We ended up extracting the list by logging into every fully patched version of Windows Server and exporting the proper registry key values. The full list can be found here.
A new SSL/TLS vulnerabilty was recently discovered dubbed “FREAK“. Originally it was thought that only OpenSSL was vulnerable, however, Microsoft just issued an advisory (3046015) describing the affected versions of Windows. The default configuration of Windows 2003 is vulnerable, however, Windows 2008 and above are not affected in the default configuration. The Best Practices template in IIS Crypto solves this by removing the affected cipher suites.