How to Enable the NotPetya/Petna/Petya Vaccine
To vaccinate your computer so that you are unable to get infected with the current strain of NotPetya/Petya/Petna (yeah, this naming is annoying), simply create a file called perfc in the C:\Windows folder and make it read only. For those who want a quick and easy way to perform this task, Lawrence Abrams has created a batch file that performs this step for you.
Source: https://www.bleepingcomputer.com/news/security/vaccine-not-killswitch-found-...