Possible Vaccine was discovered: Vaccine, not Killswitch, Found for Petya (NotPetya) Ransomware Outbreak
"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."
I welcome the Extra DAT availability, but what I haven't seen anywhere, is confirmation that today's 8573 DAT includes the Petya variant. I need to decide whether or not to deploy the Extra DAT. This vital information about today's 8573 DAT is missing.