Not OP, but he is right. I just walked out of work, where I had to reverse the sample. It indeed uses EternalBlue (attacks by enumerating local network IPs with Windows APIs and randomly scanning the internet). Apart from that, it overwrites the MBR with a custom bootloader and schedules a restart ("shutdown /t /r") as SYSTEM in a random amount of time. After rebooting, it fakes a chkdsk and meanwhile, encrypts your files.

It is also true that it uses PsExec to spread.

TL;DR good old Petya ransomware (old as shit) with a copy/pasted EternalBlue-based spreading method. Nothing new.