The Security Defenders are working overtime today to stop WCry [ WannaCry ]. Right now, 45,000 attacks of the WannaCry ransomware are reported in 74 countries around the world. This is pretty bad, there are reports of Hospitals being shut down due to this, Service Providers shutting down their computers and many other reports out there of companies affected.
MS17-010 is the Patch MS released in April to address the vulnerability this piece of ransomware is using and if this is not on your system; you are vulnerable.
Close Firewall ports 445/139 & 3389.
Fig 1, Machine infected with WCry Image via Twitter Malware Hunter Team.