There are 4.1 million Windows endpoints exposed online via Remote Desktop Protocol (RDP) Researchers at Rapid7 found 11 million open 3389/TCP endpoints. RDP is effectively a way to expose keyboard, mouse and ultimately a Windows desktop over the network. Microsoft addressed dozens of vulnerabilities in the Remote Desktop protocol over the past fifteen years. Over 80% of exposed endpoints supported CredSSP security protocol, meaning that the RDP session was highly secured. Over 15% of endpoints indicated that they didnt support SSL/TLS.”]
Source: http://securityaffairs.co/wordpress/62004/hacking/rdp-exposure-report.html