A computer running a Windows Server is seen connected into a network server in an office building in Washington, DC on May 13, 2017. 
International investigators hunted on May 13 for those behind an unprecedented cyber-attack that affected systems in dozens of countries, including at banks, hospitals and government agencies, as security experts sought to contain the fallout. The assault, which began Friday and was being described as the biggest-ever cyber ransom attack, struck state agencies and major companies around the world -- from Russian banks and British hospitals to FedEx and European car factories. / AFP PHOTO / Andrew CABALLERO-REYNOLDS        (Photo credit should read ANDREW CABALLERO-REYNOLDS/AFP/Getty Images)