The large-scale cyber attack has hit FedEx, Britain's health system and infected computers in over 100 countries.
The ransomware attack hit Britain's health service, forcing effected hospitals to close wards and emergency rooms. Attacks have also been reported in Spain, Portugal and Russia.
Ransomware is requiring infected users to pay over $300 USD in Bitcoin.
It is believed that the hackers used the NSA method for bypassing Windows 10 security, leaked earlier this year.
Software company, Avast, has said it observed over 60,000 infections in 99 countries.