This post aims to provide the reason on why Windows client systems get the following error when trying to access a Window server using RDP
Remote desktop connection authentication error due to CredSSP encryption oracle remediation
After doing a through search on the internet, it seems this issue is caused when a client Windows machine that is patched with a CredSSP (Credential Security Support Provider protocol) update for CVE-2018-0886 tries to access a remote Windows server that is not updated with the required patched.
Though it i advisable to ensure the WIndows server is patched properly, a quick fix is to tweek the client system to ignore the security warning by following the below step:
- In the Windows client system run the Windows Command Prompt tool using an Administrator privilege.
- Type the following command that will do the magic in the registry setting:
- reg add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System\CredSSP\Parameters /v AllowEncryptionOracle /t REG_DWORD /d 2 /f