Computer Help and Support

Lawrence Abrams (aka Grinler) owner/admin @Bleepingcomputer.com posted a "vaccination" for this Petya/not Petya whatever it is:

https://www.bleepingcomputer.com/news/security/vaccine-not-killswitch-found-for-petya-notpetya-ransomware-outbreak/

Because of the ransomware's global outreach, many researchers flocked to analyze it, hoping to find a loophole in its encryption or a killswitch domain that would stop it from spreading, similar to WannaCry.

While analyzing the ransomware's inner workings, Serper was the first to discover that NotPetya would search for a local file and would exit its encryption routine if that file already existed on disk.

The researcher's initial findings have been later confirmed by other security researchers, such as PT Security, TrustedSec, and Emsisoft.

This means victims can create that file on their PCs, set it to read-only, and block the NotPetya ransomware from executing.