http://www.computerweekly.com/news/450418770/Businesses-urged-to-apply-Windows-patch-to-avert-WannaCry-attacks OK this is aimed at businesses but I doubt wannacry cares who owns the system it encrypts If you are at all concerned the tl;dr is you need the MS17-010 patch on your system, if you use windows update you should get it automatically, not everyone keeps their systems up to date though You can check the details on the Microsoft site here https://technet.microsoft.com/en-us/library/security/ms17-010.aspx