PowerShell remoting (WinRM) over HTTPS using a AD CS PKI (CA) signed client Certificate

This is a guide to show you how to enroll your servers/desktops to allow powershell remoting (WINRM) over HTTPS

Assumptions

  • You have a working Root CA on the ADDS environment – Guide
  • CRL and AIA is configured properly – Guide
  • Root CA cert is pushed out to all Servers/Desktops – This happens by default

Contents

  1. Setup CA Certificate template
  2. Deploy Auto-enrolled Certificates via Group Policy
  3. Powershell logon script to set the WinRM listener
  4. Deploy the script as a logon script via Group Policy
  5. Testing
1 – Setup CA Certificate template to allow Client Servers/Desktops to checkout the certificate from the CA

Connect to the The Certification Authority Microsoft Management Console (MMC)

Navigate to Certificate Templates > Manage

On the “Certificate templates Console” window > Select Web Server > Duplicate Template

Under the new Template window Set the following attributes

General – Pick a Name and Validity Period – This is up to you

Compatibility – Set the compatibility attributes (You can leave this on the default values, It up to you)

Subject Name – Set ‘Subject Name’ attributes (Important)

Security – Add “Domain Computers” Security Group and Set the following permissions

  • Read – Allow
  • Enroll – Allow
  • Autoenroll – Allow

Click “OK” to save and close out of “Certificate template console”

Issue to the new template

Go back to the “The Certification Authority Microsoft Management Console” (MMC)

Under templates (Right click the empty space) > Select New > Certificate template to Issue

Under the Enable Certificate template window > Select the Template you just created

Allow few minutes for ADDS to replicate and pick up the changes with in the forest

2 – Deploy Auto-enrolled Certificates via Group Policy

Create a new GPO

Windows Settings > Security Settings > Public Key Policies/Certificate Services Client – Auto-Enrollment Settings

Link the GPO to the relevant OU with in your ADDS environment

Note – You can push out the root CA cert as a trusted root certificate with this same policy if you want to force computers to pick up the CA cert,

Testing

If you need to test it gpupdate/force or reboot your test machine, The Server VM/PC will pickup a certificate from ADCS PKI

3 – Powershell logon script to set the WINRM listener

Dry run

  • Setup the log file
  • Check for the Certificate matching the machines FQDN Auto-enrolled from AD CS
  • If exist
    • Set up the HTTPS WInRM listener and bind the certificate
    • Write log
  • else
    • Write log
#Malinda Rathnayake- 2020
#
#variable
$Date = Get-Date -Format "dd_MM_yy"
$port=5986
$SessionRunTime = Get-Date -Format "dd_yyyy_HH-mm"
#
#Setup Logs folder and log File
$ScriptVersion = '1.0'
$locallogPath = "C:\_Scripts\_Logs\WINRM_HTTPS_ListenerBinding"
#
$logging_Folder = (New-Item -Path $locallogPath -ItemType Directory -Name $Date -Force)
$ScriptSessionlogFile = New-Item $logging_Folder\ScriptSessionLog_$SessionRunTime.txt -Force
$ScriptSessionlogFilePath = $ScriptSessionlogFile.VersionInfo.FileName
#
#Check for the the auto-enrolled SSL Cert
$RootCA = "Company-Root-CA" #change This
$hostname = ([System.Net.Dns]::GetHostByName(($env:computerName))).Hostname
$certinfo = (Get-ChildItem -Path Cert:\LocalMachine\My\ |? {($_.Subject -Like "CN=$hostname") -and ($_.Issuer -Like "CN=$RootCA*")})
$certThumbprint = $certinfo.Thumbprint
#
#Script-------------------------------------------------------
#
#Remove the existing WInRM Listener if there is any
Get-ChildItem WSMan:\Localhost\Listener | Where -Property Keys -eq "Transport=HTTPS" | Remove-Item -Recurse -Force
#
#If the client certificate exists Setup the WinRM HTTPS listener with the cert else Write log
if ($certThumbprint){
#
New-Item -Path WSMan:\Localhost\Listener -Transport HTTPS -Address * -CertificateThumbprint $certThumbprint -HostName $hostname -Force
#
netsh advfirewall firewall add rule name="Windows Remote Management (HTTPS-In)" dir=in action=allow protocol=TCP localport=$port
#
Add-Content -Path $ScriptSessionlogFilePath -Value "Certbinding with the HTTPS WinRM HTTPS Listener Completed"
Add-Content -Path $ScriptSessionlogFilePath -Value "$certinfo.Subject"}
else{
Add-Content -Path $ScriptSessionlogFilePath -Value "No Cert matching the Server FQDN found, Please run gpupdate/force or reboot the system"
}

Script is commented with Explaining each section (should have done functions but i was pressed for time, never got around to do it, if you do fix it up and improve this please let me know in the comments :D)

5 – Deploy the script as a logon script via Group Policy

Setup a GPO and set this script as a logon Powershell script

Im using a user policy with GPO Loop-back processing set to Merge applied to the server OU

Testing

To confirm WinRM is listening on HTTPS, type the following commands:

winrm enumerate winrm/config/listener
Winrm get http://schemas.microsoft.com/wbem/wsman/1/config

Sources that helped me

https://docs.microsoft.com/en-us/troubleshoot/windows-client/system-management-components/configure-winrm-for-https

https://gmusumeci.medium.com/get-rid-of-those-annoying-self-signed-certificates-with-microsoft-certificate-services-part-3-9d4b8e819f45

http://vcloud-lab.com/entries/powershell/powershell-remoting-over-https-using-self-signed-ssl-certificate

Azure AD Sync Connect No-Start-Connection status

Issue

Received the following error from the Azure AD stating that Password Synchronization was not working on the tenant.

When i manually initiate a delta sync, i see the following logs

"The Specified Domain either does not exist or could not be contacted"

(click to enlarge)

Checked the following

  • Restarted ADsync Services
  • Resolve the ADDS Domain FQDN and DNS – Working
  • Test required ports for AD-sync using portqry – issues with the Primary ADDS server defined on the DNS values

Root Cause

Turns out the Domain controller Defined as the primary DNS value was pointing was going thorough updates, its responding on the DNS but doesn’t return any data (Brown-out state)

Assumption

when checking DNS since the DNS server is connecting, Windows doesn’t check the secondary and tertiary servers defined under DNS servers.

This might happen if you are using a ADDS server via a S2S tunnel/MPLS when the latency goes high

Resolution

Check make sure your ADDS-DNS servers defined on AD-SYNC server are alive and responding

in my case i just updated the “Primary” DNS value with the umbrella Appliance IP (this act as a proxy and handle the fail-over)

Hybrid Exchange mailbox On-boarding : Target user already has a primary mailbox – Fix

During an Office 365 migration on a Hybrid environment with AAD Connectran into the following scenario:

  • Hybrid Co-Existence Environment with AAD-Sync
  • User [email protected] has a mailbox on-premises. Jon is represented as a Mail User in the cloud with an office 365 license
  • [email protected] had a cloud-only mailbox prior to the initial AD-sync was run
  • A user account is registered as a mail-user and has a valid license attached
  • During the office 365 Remote mailbox move, we end up with the following error during validation and removing the immutable ID and remapping to on-premise account won’t fix the issue
Target user 'Sam fisher' already has a primary mailbox.
+ CategoryInfo : InvalidArgument: (tsu:MailboxOrMailUserIdParameter) [New-MoveRequest], RecipientTaskException
+ FullyQualifiedErrorId : [Server=Pl-EX001,RequestId=19e90208-e39d-42bc-bde3-ee0db6375b8a,TimeStamp=11/6/2019 4:10:43 PM] [FailureCategory=Cmdlet-RecipientTaskException] 9418C1E1,Microsoft.Exchange.Management.Migration.MailboxRep
lication.MoveRequest.NewMoveRequest
+ PSComputerName : Pl-ex001.Paladin.org

It turns out this happens due to an unclean cloud object on MSOL, This is because Exchange online keeps pointers that indicate that there used to be a mailbox in the cloud for this user

Option 1 (nuclear option)

to fix this problem was to delete *MSOL User Object* for Sam and re-sync it from on-premises. This would delete [email protected] from the cloud – but it will delete him/her from all workloads, not only Exchange. This is problematic because Sam is already using Teams, One-drive, SharePoint.

Option 2

Clean up only the office 365 mailbox pointer information

PS C:\> Set-User [email protected] -PermanentlyClearPreviousMailboxInfo 
Confirm
Confirm
Are you sure you want to perform this action?
Delete all existing information about user "[email protected]"?. This operation will clear existing values from
Previous home MDB and Previous Mailbox GUID of the user. After deletion, reconnecting to the previous mailbox that
existed in the cloud will not be possible and any content it had will be unrecoverable PERMANENTLY. Do you want to
continue?
[Y] Yes [A] Yes to All [N] No [L] No to All [?] Help (default is "Y"): a

Executing this leaves you with a clean object without the duplicate-mailbox problem,

in some cases when you run this command you will get the following output 

 “Command completed successfully, but no user settings were changed.”

If this happens

Remove the license from the user temporarily and run the command to remove previous mailbox data

then you can re-add the license