Revision Note: V1.1 (December 8, 2015): Advisory updated to include more information about disabling DES by default in Windows 7 and Windows Server 2008 R2 and later operating systems. The update allows DES to be used between client and server to address scenarios in which DES is still required for application compatibility reasons.
Summary: Microsoft is announcing the availability of an update to harden scenarios in which Data Encryption Standard (DES) encryption keys are used with accounts to ensure that domain users, services, and computers that support other encryption types are not vulnerable to credential theft or elevation of privilege attacks. DES is considered a weak cipher due to well-known brute force and faster than brute force attacks. The cryptographic algorithm has also been removed from the standard [RFC 6649]. To further protect our users, Microsoft has disabled DES by default in Windows 7 and Windows Server 2008 R2 and later operating systems. However, this update does allow DES to be used between client and server to address scenarios in which DES is still required for application compatibility reasons. The improvement is part of ongoing efforts to bolster the effectiveness of encryption in Windows and still support legacy line-of-business (LOB) applications.