Tag Archives: error

Can’t RDP to Server after Windows Patch (CredSSP)

I was preparing to remote into a virtual machine to do some maintenance when I encountered an error.

“An authentication error has occurred.
The function requested is not supported

Remote computer: [Computer Name]
This could be due to CredSSP encryption oracle remediation.
For more information, see https://go.microsoft.com/fwlink/?linkid=866660”

Information from the link in the error:

Credential Security Support Provider protocol (CredSSP) is an authentication provider that processes authentication requests for other applications.

A remote code execution vulnerability exists in unpatched versions of CredSSP. An attacker who successfully exploits this vulnerability could relay user credentials to execute code on the target system. Any application that depends on CredSSP for authentication may be vulnerable to this type of attack.

This security update addresses the vulnerability by correcting how CredSSP validates requests during the authentication process.

Options:

The bottom line is that in order to RDP into the target server both computers need to have the update installed.  In my case, my local machine was updated, but the target machine was not yet updated.  This target machine did not have automatic updates turned on and was an Azure VM.  I could have contacted support, or turned on automatic updates from the portal, but the reality was I needed to get into the machine quickly to handle an emergency fix.  Due to the simple architecture (stand-alone VM) I could not push the patch via SCCM or GPO.

Work-around 1:

Continue reading Can’t RDP to Server after Windows Patch (CredSSP)

Resolve SQL Server Fatal error: cannot create ‘R_TempDir’

I was trying to test an install of R in SQL Server 2016 and when running a script I received this error: Fatal error: cannot create ‘R_TempDir’

Following the instructions here, I enabled external scripts, restarted the sql server service, and then tried to run the following test script:

This is when the fatal error occurred.  As the error suggests, R is having some issues creating a temporary directory.  After some internet searching and trial and error I got past the issue.

Enable  8dot3 File Names

R configuration uses the 8dot3 file name convention, also known as “short names”.  To enable this on windows 10, run the following command in CMD (command prompt):

For more options and information look here: https://support.microsoft.com/en-us/kb/121007

Give access to the working directory to R

Locate and open “rlauncher.config” file in a text editor.  This file will be under the “<sqlserver_instance>\binn” directory.  Take a look at the location of WORKING_DIRECTORY.  This should have a “short name” file path.  The path should be something like “<sqlserver_instance>\EXTENS~1”, and “\EXTENS~1” is equivalent to “\ExtensibilityData”.  We need to give access to R to this folder. I did this by changing the permissions to full control to everyone.  You may want to be more restrictive here, but in my case this did not matter.

  • Right click folder > Properties > Security tab > Advanced > Add
  • Select a principal (I entered “Everyone”)
  • Tick “Full control” under basic permissions and click “OK”
  • Tick “Replace all child object and permissions entries with inheritable permissions entries from this object” and click “OK”

Now if you rerun the script above you should get a result of “hello, 1”.