On June 27th, Microsoft began detecting a new malware called Petya ransomware. It’s said to be more dangerous than “Wannacry.” Learn more at . . .
https://blogs.technet.microsoft.com/mmpc/2017/06/27/new-ransomware-old-techniques-petya-adds-worm-capabilities/
Fortunately, anyone running Windows Defender and Norton Security is already protected from this new variant, which uses the Eternal Blue exploit in Windows computers.
Here is another simple way to protect against this particular attack:
http://www.zdnet.com/article/create-a-single-file-to-protect-yourself-from-latest-ransomware-attack/