A security researcher registered a kill switchs domain (iuqerfsodp9ifjaposdfjhgosurijfaewrwergwea.com) that WannaCry checked to make sure was unregistered before starting to encrypt files. A different variant of the ransomware was coded to contact a different domain. Europol chief Rob Wainwright told the BBC, Companies need to. make sure they have updated their systems and patched where they should before staff arrived for work on Monday morning”]