Microsoft warns ransomware cyber-attack is a wake-up call Microsoft says a cyber-attack that has hit 150 countries since Friday should be treated by governments around the world as a wake-up call. The computing giant said software vulnerabilities hoarded by governments has caused widespread damage. The latest virus, exploits a flaw in a version of Microsoft Windows first identified by US intelligence. There have been warnings of further ransomware attacks as people return to work today. Firms have had experts working over the weekend to prevent new infections. The virus took control of users' files and demanded 300 dollar payments to restore access. Experts say the spread of the virus slowed over the weekend but the respite might only be brief. SOURCE: BBC NEWS