It is basically WannaCry without the kill switch. It is using the same exploits (EternalBlue). Not some recent zero-day, but sloppy patching.
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.
As for the tools: just IDA Pro, really, if you don't count the standard stuff: a VM to avoid getting the host infected (VirtualBox), Burp (to analyze malware HTTP traffic), etc. Nothing too fancy.