Microsoft recently released two patches that will likely impact your future pentests. The first was KB2871997. Some have dubbed this the "Pass the Hash Fix" but it is hardly that. The second patch that will likely impact your pentests is KB2928120.
more here........http://www.pwnag3.com/2014/05/what-did-microsoft-just-break-with.html
more here........http://www.pwnag3.com/2014/05/what-did-microsoft-just-break-with.html