Um eine Infektion mit NotPetya/Petya/Petna/SortaPetya im Vorhinein zu verhindern, kann man bestimme Dateien im Ordner C:\Windows anlegen. Der Sicherheitsforscher Lawrence Adams hat dafür eine Batch-Datei mit folgendem Inhalt entwickelt:

@echo off

echo KJ-NetworX GmbH KillSwitch for NotPetya/Petya/Petna/SortaPetya
echo https://www.heise.de/security/meldung/Alles-was-wir-bisher-ueber-den-Petya-NotPetya-Ausbruch-wissen-3757607.html

echo Administrative permissions required. Detecting permissions...
echo.

net session >nul 2>&1

if %errorLevel% == 0 (
if exist C:\Windows\perfc (
echo Computer already vaccinated for NotPetya/Petya/Petna/SortaPetya.
echo.
) else (
echo This is a NotPetya/Petya/Petna/SortaPetya Vaccination file. Do not remove as it protects you from being encrypted by Petya. > C:\Windows\perfc
echo This is a NotPetya/Petya/Petna/SortaPetya Vaccination file. Do not remove as it protects you from being encrypted by Petya. > C:\Windows\perfc.dll
echo This is a NotPetya/Petya/Petna/SortaPetya Vaccination file. Do not remove as it protects you from being encrypted by Petya. > C:\Windows\perfc.dat

attrib +R C:\Windows\perfc
attrib +R C:\Windows\perfc.dll
attrib +R C:\Windows\perfc.dat

echo Computer vaccinated for current version of NotPetya/Petya/Petna/SortaPetya.
echo.
)
) else (
echo Failure: You must run this batch file as Administrator.
)