Thursday, May 10, 2018

[Solved] CredSSP encryption oracle remediation error

Today after the MS patch installation, most of them experience an issue with the Remote desktop. 

An Authentication error has occurred.

The function requested is not supported.

Remote computer: <#servername#>

This could be due to CredSSP encryption oracle remediation

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This will be effecting to the Windows Server and the Win 7/10 environments as well.

when I checked the hotfix details I saw that yesterday there were few updates and this will cause the issue.

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While I'm searching this on the internet found that this is because of the below mentioned three hotfixes.

KB4103725 (Windows 8/10)
KB4103727 (Server 2016/2012)
KB4103718 (Windows 7)

If you have them installed frequently, uninstall them and check.

But as a quick fix you can add a registry value and fix this the details are mentioned bellow,

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Windows Registry Editor Version 5.00
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP]
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters]
"AllowEncryptionOracle"=dword:00000002

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Copy and paste this into a notepad and save as a .REG file. Then run the Registry editor as a run as admin.

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Import this registry file and once that is done you will be able to see that that new registry value is set as below,

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Restart your PC after that and see the status. Now you will be able to RDP again.

For me this works without restarting the PC.

Note :  This is not a permanent fix. Once the MS Patch is released, need to remove this.

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