It's using an exploit leaked by the CIA whistleblower. Cheers, pal.
Very effective against NHS systems because they've left older SMB protocol versions running in order to service XP-based clients, and there's a lot of digital real-estate not updated to 7 or above, for very good reasons.
So, this highlights the danger of running un-supported Operating Systems, does it? Perhaps it highlights the disadvantage of continuously changing operating systems in this rapid release format that Microsoft have switched to. Will there be a version of Windows 10 in, say, 10 years time that is deemed 'unsupported'? We heard a while back that Windows 10 was the last version of Windows you'll ever get, because they're ditching that idea of releasing versions. Yet within 2 years we are onto 'Creators edition', potentially back to how it was. Good or bad? We've yet to see.
Will this be a lesson for developers to produce something that is "buy once"?