This month’s Microsoft Patch Tuesday included a very high-risk vulnerability (CVE-2019-0708, aka BlueKeep) in Remote Desktop that impacts Windows XP, Windows 7, Server 2003, Server 2008, and Server 2008 R2. This vulnerability allows an unauthenticated attacker (or malware) to execute code on the vulnerable system. It is very likely that PoC code will be published soon, and this may result in a WannaCry-style attack.
UPDATE: Network Level Authentication (NLA) partially mitigates this vulnerability. QID 90788 (Microsoft Windows Network Level Authentication Disabled) can be used to find hosts that have NLA disabled. This forces the attacker to have valid credentials in order to perform RCE.
UPDATE: A new remote (unauthenticated) check was released under QID 91541. See below for details.