Microsoft is announcing the availability of an update for Microsoft .NET Framework that disables RC4 in Transport Layer Security (TLS) through the modification of the system registry. Use of RC4 in TLS could allow an attacker to perform man-in-the-middle attacks and recover plaintext from encrypted sessions.
more here...........https://technet.microsoft.com/library/security/2960358
more here...........https://technet.microsoft.com/library/security/2960358