KB4103727 Breaks RDP/Remote Desktop Gateway

This morning we awoke to screams from users not being able to login to our remote desktop servers.

KB4103727 has been released which switches a flag to protect against the CredSSP attack.

The quickest way to fix this to get your users working is to patch your domain controller with the May updates and use group policy to push out a change

You can manually add this to the registry for desktop clients

[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters] "AllowEncryptionOracle"=dword:00000002

or via command line

reg add "HKLM\Software\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters" /f /v AllowEncryptionOracle /t REG_DWORD /d 2

To fix this problem, the May updates need to be installed on all servers and workstations.

More information:

 

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