Security firm Kaspersky Lab has recorded more than 45,000 ransomware attacks in the last 10 hours, most of which were targeting Russia. The ransomware, “WannaCry,” has been spreading through a Microsoft Windows exploit called “EternalBlue,” which Microsoft released a patch for in March, reports CNN.  

Users of infected machines have six hours to pay the ransom, and the cost goes up every few hours, says Kurt Baumgartner, principal security researcher at Kapersky Lab.