WannaCry (AKA WanaCrypt0r, WCry, Wannageddon or another day of cyberinfamy), which marries ransomware with worm-type spread targeted at Microsoft Windows operating systems, is the "the worst ransomware outbreak in history." But according to Jakub Křoustek, a lead on Avast’s Threat Intelligence team, it could easily have been avoided through proper patch management. The attack, which began on May 12, has cost victims as much as $4 billion.