The Ransomware Wannacry(pt) was originally created by the NSA to exploit weaknesses in Windows.
Now Microsoft criticizes the Authorities for seeking out weaknesses in their Operative system and to make and store exploits/hacks.
This is not a good idea according to Microsoft and the practice is partly to blame for the current spreading of Wannacry which is one of the most significant cyberattacks ever recorded.
Microsoft seems to be worried about the governments acting as hackers and want them to agree on some ground rules for cyber war; like the Geneva conventions.
In any case the authorities should share the found weaknesses with Microsoft so they can be patched rather than storing them as a weapon to use.
Instead of developing hacking tools in secret and holding them for use against adversaries, governments and intelligence agencies should share weaknesses they find with Microsoft and other software makers so that vulnerabilities can be repaired
Microsoft go as far as they can in criticizing the governments of the world - including (and especially) the US:
The governments of the world should treat this attack as a wake-up call,” Smith said. “They need to take a different approach and adhere in cyberspace to the same rules applied to weapons in the physical world.
If one should speculate; it would seem that Microsoft is uncomfortable with being reigned by a government that systematically hacks and exploits their system; a system they need to deliver world wide.
If the US governments wants Microsoft "in" on an exploit they can simply instruct them which is not that far fetched given the recent history...
That spells bad business to Microsoft.
If you are infected use this MS bulletin