Well they only could have done that via cooperation from Silicon Valley through a AMD and Intel chip backdoor. From what version chip this has been achieved probably won’t be revealed, as the speculation on it goes on: http://wccftech.com/intel-possibly-amd-chips-permanent-backdoors-planted-nsa/
Some technical experts say that because of the nature of the encryption chip code the whole idea of an existing back door is very unlikely.
Insofar as the MS update process plays a role in this back dooring has to be seen, but it is not very plausible. Anyway with the ongoing surveillance it is a good advice to users to assume that everything one does in private on the Internet should actually be considered as uttered in public. Guys and gals we’re in this together and speculation has not brought much. The innocence of the common user as before the so-called revelations were leaked won’t return. This the more so as the real backbone of the Internet is held and maintained by the US of A,
polonus