Showing posts with label NT AUTHORITY\Authenticated Users. Show all posts
Showing posts with label NT AUTHORITY\Authenticated Users. Show all posts

Monday, May 18, 2015

The Case of the Mysterious Blank Desktop, part 2?

Hello everyone, 

I recently experienced an issues login into a Windows Server 2008 R2. Whenever I would log in, whether through RDP or VM Console, the only thing that would load was a blank desktop. No errors, no windows, no explorer. I wasn't able to use Remote Tools, but I was able to use PSRemote and from there was was able to pull the following log:

[HOSTNAME]: PS C:\Users\USERNAME\Documents> Get-EventLog -LogName Application | ?{$_.Source -eq 'Winlogon'} | ?{$_.EntryType -eq 'Warning'} | select -First 1 | fl * -Force


EventID            : 4006
MachineName        : HOSTNAME.DOMAIN.com
Data               : {5, 0, 0, 0}
Index              : 40795
Category           : (0)
CategoryNumber     : 0
EntryType          : Warning
Message            : The Windows logon process has failed to spawn a user application. Application name: . Command line
                      parameters: C:\Windows\system32\userinit.exe.
Source             : Winlogon
ReplacementStrings : {, C:\Windows\system32\userinit.exe}
InstanceId         : 2147487654
TimeGenerated      : 5/18/2015 8:47:26 PM
TimeWritten        : 5/18/2015 8:47:26 PM
UserName           :
Site               :
Container          :

I quickly pulled out Google and found the following article, but to my demise after checking the local group I found that the users were already added.

[HOSTNAME]: PS C:\Users\USERNAME\Documents> net localgroup users
Alias name     users
Comment        Users are prevented from making accidental or intentional system-wide changes and can run most applications

Members

-------------------------------------------------------------------------------
NT AUTHORITY\Authenticated Users
NT AUTHORITY\INTERACTIVE
DOMAIN\Domain Admins
DOMAIN\Domain Users
The command completed successfully.

Great so now what? I searched the internet trying to find someone who might have experienced a similar issue but i only found similar articles to the one linked above. I attempted to reboot, to remove the users Authenticated Users/Interactive off the group, reboot, add them again and reboot once again, but nothing.

I did have some idea of what might be causing the issue based on the article though, so I attempted moving the computer to a different OU that doesn't require UAC to be turned on. I updated the group policy and rebooted but still nothing. Frustrated I went to to Regedit and attempted to load the UAC settings to find out if it was turned on or off by using the following command that I got from this article.

[HOSTNAME]: PS C:\Users\USERNAME\Documents> (Get-ItemProperty HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Policies\System).EnableLUA

To my surprise I got nothing. Null return value. I thought that was weird, so I confirmed on a different server with the same version to ensure that the command was correct, and it was returning a result of 0. So I re-added the setting using the following command, also found in the article. 

[HOSTNAME]: PS C:\Users\USERNAME\Documents> Set-ItemProperty -Path registry::HKEY_LOCAL_MACHINE\Software\Microsoft\Windows\CurrentVersion\policies\system -Name EnableLUA -Value 0

I rebooted and the server logged back in without any issues. I have no idea how this registry could have been deleted, or why it had this effect so if anyone has any more information please be sure to share.

I hope this might help someone out there. Do let me know if you have any questions, issues or comments. 

Kind regards, 
Me.