Mar 062022
 
Azure AD SSO with Horizon

Whether deploying VDI for the first time or troubleshooting existing Azure AD SSO issues for an existing environment, special consideration must be made for Microsoft Azure AD SSO and VDI.

When you implement and use Microsoft 365 and Office 365 in a VDI environment, you should have your environment configured to handle Azure AD SSO for a seamless user experience, and to avoid numerous login prompts when accessing these services.

Microsoft Azure Active Directory has two different methods for handling SSO (Single Sign On), these include SSO via a Primary Refresh Token (PRT) and Azure Seamless SSO. In this post, I’ll explain the differences, and when to use which one.

Microsoft Azure AD SSO and VDI

What does Azure AD SSO do?

Azure AD SSO allows your domain joined Windows workstations (and Windows Servers) to have a Single Sign On experience so that users can have an single sign-on integrated experience when accessing Microsoft 365 and/or Office 365.

When Azure AD SSO is enabled and functioning, your users will not be prompted nor have to log on to Microsoft 365 or Office 365 applications or services (including web services) as all this will be handled transparently in the background with Azure AD SSO.

For VDI environments, especially non-persistent VDI (VMware Instant Clones), this is an important function so that users are not prompted to login every time they launch an Office 365 application.

Persistent VDI is not complex and doesn’t have any special considerations for Azure AD SSO, as it will function the same way as traditional workstations, however non-persistent VDI requires special planning.

Please Note: Organizations often associate the Office 365 login prompts to activation issues when in fact activation is functioning fine, however Azure AD SSO is either not enabled, incorrect configured, or not functioning which is why the users are being prompted for login credentials every time they establish a new session with non-persistent VDI. After reading this guide, it should allow you to resolve the issue of Office 365 login prompts on VDI non-persistent and Instant Clone VMs.

Azure AD SSO methods

There are two different ways to perform Azure AD SSO in an environment that is not using ADFS. These are:

  • Azure AD SSO via Primary Refresh Token
  • Azure AD Seamless SSO

Both accomplish the same task, but were created at different times, have different purposes, and are used for different scenarios. We’ll explore this below so that you can understand how each works.

Screenshot of a Hybrid Azure AD Joined login
Hybrid Azure AD Joined Login

Fun fact: You can have both Azure AD SSO via PRT and Azure AD Seamless SSO configured at the same time to service your Active Directory domain, devices, and users.

Azure SSO via Primary Refresh Token

When using Azure SSO via Primary Refresh Token, SSO requests are performed by Windows Workstations (or Windows Servers), that are Hybrid Azure AD Joined. When a device is Hybrid Azure AD Joined, it is joined both to your on-premise Active Directory domain, as well registered to your Azure Active Directory.

Azure SSO via Primary Refresh token requires the Windows instance to be running Windows 10 (or later), and/or Windows Server 2016 (or later), as well the Windows instance has to be Azure Hybrid AD joined. If you meet these requirements, SSO with PRT will be performed transparently in the background.

If you require your non-persistent VDI VMs to be Hybrid Azure AD joined and require Azure AD SSO with PRT, special considerations and steps are required:

This includes:

  • Scripts to automatically unjoin non-persistent (Instant Clone) VDI VMs from Azure AD on logoff.
  • Scripts to cleanup old entries on Azure AD

If you properly deploy this, it should function. If you don’t require your non-persistent VDI VMs to be Hybrid Azure AD joined, then Azure AD Seamless SSO may be better for your environment.

Azure AD Seamless SSO

Microsoft Azure AD Seamless SSO after configured and implemented, handles Azure AD SSO requests without the requirement of the device being Hybrid Azure AD joined.

Seamless SSO works on Windows instances instances running Windows 7 (or later, including Windows 10 and Windows 11), and does NOT require the the device to be Hybrid joined.

Seamless SSO allows your Windows instances to access Azure related services (such as Microsoft 365 and Office 365) and provides a single sign-on experience.

This may be the easier method to use when deploying non-persistent VDI (VMware Instant Clones), if you want to implement SSO with Azure, but do not have the requirement of Hybrid AD joining your devices.

Additionally, by using Seamless SSO, you do not need to implement the require log-off and maintenance scripts mentioned in the above section (for Azure AD SSO via PRT).

To use Azure AD Seamless SSO with non-persistent VDI, you must configure and implement Seamless SSO, as well as perform one of the following to make sure your devices do not attempt to Hybrid AD join:

  • Exclude the non-persistent VDI computer OU containers from Azure AD Connect synchronization to Azure AD
  • Implement a registry key on your non-persistent (Instant Clone) golden image, to disable Hybrid Azure AD joining.

To disable Hybrid Azure AD join on Windows, create the registry key on your Windows image below:

HKLM\SOFTWARE\Policies\Microsoft\Windows\WorkplaceJoin: "BlockAADWorkplaceJoin"=dword:00000001

Conclusion

Different methods can be used to implement SSO with Active Directory and Azure AD as stated above. Use the method that will be the easiest to maintain and provide support for the applications and services you need to access. And remember, you can also implement and use both methods in your environment!

After configuring Azure AD SSO, you’ll still be required to implement the relevant GPOs to configure Microsoft 365 and Office 365 behavior in your environment.

Additional Resources

Please see below for additional information and resources:

Jan 292018
 
Microsoft Azure AD Connect Agent Updater

I’m writing today to share about an experience I had hours ago, where the Microsoft Azure AD Connect software (specifically the Azure AD Connect Agent Updater) actually updated itself, and restarted the server it’s installed on, all during production hours.

Pretty serious stuff hey?

It all happened around 12:50PM (Mountain Time)… I received a notification that a service had been marked as failed on the particular server (notification from my monitoring/management system), and I went to investigate. I noticed that the server was actually gracefully restarted. After logging in, I came across these event logs.

Event ID 34004

Event ID 1074

Both Event ID 34004 and Event ID 1074 were logged, reporting both that it had downloaded an update, installed, and the installer initiated a restart.

I thought: no way should auto-updating be enabled, and I still can’t actually confirm it either. I found this article which explains of an automatic update feature:

https://docs.microsoft.com/en-us/azure/active-directory/connect/active-directory-aadconnect-feature-automatic-upgrade

However, not only did I not meet the criteria of auto-update being enabled, but upon further investigation it was actually disabled by running the powershell command:

Get-ADSyncAutoUpgrade

As you can see below the command returned as “suspended”.

Get-ADSyncAutoUpgrade

After spending tons more time searching and not finding anything, I decided I’d just disable the service called “Microsoft Azure AD Connect Agent Updater”. In my environment it was running and set to “Automatic (Delayed)”, but I stopped the service and changed it to “Disabled”.

It’s not reflected in the picture below, but this is the service that was responsable for updating and restarting the server. Since I’ve stopped it, it appears everything is functioning correctly, except auto-updating.

Microsoft Azure AD Connect Agent Updater

Jan 212018
 
Azure AD

This weekend I configured Azure AD Connect for pass through authentication for my on-premise Active Directory domain. This was a first for me and extremely easy to do, however there was a few issues with my firewall and SSL content filtering and scanning rules which was blocking the connection. I figured I’d create a post providing some information you’ll need to get this setup and running quickly.

In my environment, I have a Sophos UTM firewall which provides firewall services (port blocking), as well as HTTP and HTTPs scanning and filtering (web filtering).

The Problem

After running the Azure AD Connect wizard, all went good however there was an error at the end of the wizard notifying that synchronization was configured but is not occurring due to firewall. It provided a link for more information (that actually didn’t really contain the information needed).

While this issue is occurring, you’ll notice:

-Azure AD Connect in the Azure portal is reporting that pass-through authentication is Enabled, however after expanding the item, the Authentication Agent reports a status of Inactive on your internal domain controllers.

-In the Event log, under “Applications and Services Logs”, then “Microsoft”, then “AzureADConnect”, then “AuthenticationAgent”, and finally “Admin”, you’ll see the following error event:

Event ID: 12019

Source: Microsoft Azure AD Connect Authentication Agent (Microsoft-AzureADConnect-AuthenticationAgent)

Event:
The Connector stopped working because the client certificate is not valid. Uninstall the Connector and install it again. Request ID: '{WAJAJAJA-OHYA-YAAA-YAAAA-WAKAKAKAKAKAKAK}'

This event log above is due to the SSL and HTTPs content filtering.

-Azure Pass-Through authentication won’t work

The Fix

After doing some research, I came up with the following list of ports and hosts you’ll need to allow unfiltered to a specific list of hosts.

Ports

The following ports are used by Azure AD Connect:

Port 443 – SSL

Port 5671 – TCP (From the host running the Azure AD Connect to Internet)

Hosts (DNS Hosts)

Here’s the host list:

*blob.core.windows.net
*servicebus.windows.net
*adhybridhealth.azure.com
*management.azure.com
*policykeyservice.dc.ad.msft.net
*login.windows.net
*login.microsoftonline.com
*secure.aadcdn.microsoftonline-p.com
*microsoftonline.com
*windows.net
*msappproxy.net
*mscrl.microsoft.com
*crl.microsoft.com
*ocsp.msocsp.com
*www.microsoft.com

If you’re running a Sophos UTM like I am, you’ll need to create an HTTP(s) scanning exception and then import this list in to a rule “Matching these URLs”:

^https?://([A-Za-z0-9.-]*\.)?blob.core.windows.net/
^https?://([A-Za-z0-9.-]*\.)?servicebus.windows.net/
^https?://([A-Za-z0-9.-]*\.)?adhybridhealth.azure.com/
^https?://([A-Za-z0-9.-]*\.)?management.azure.com/
^https?://([A-Za-z0-9.-]*\.)?policykeyservice.dc.ad.msft.net/
^https?://([A-Za-z0-9.-]*\.)?login.windows.net/
^https?://([A-Za-z0-9.-]*\.)?login.microsoftonline.com/
^https?://([A-Za-z0-9.-]*\.)?secure.aadcdn.microsoftonline-p.com/
^https?://([A-Za-z0-9.-]*\.)?microsoftonline.com/
^https?://([A-Za-z0-9.-]*\.)?windows.net/
^https?://([A-Za-z0-9.-]*\.)?msappproxy.net/
^https?://([A-Za-z0-9.-]*\.)?mscrl.microsoft.com/
^https?://([A-Za-z0-9.-]*\.)?crl.microsoft.com/
^https?://([A-Za-z0-9.-]*\.)?ocsp.msocsp.com/
^https?://([A-Za-z0-9.-]*\.)?www.microsoft.com/

The exception I created skips:

  • Authentication
  • Caching
  • Antivirus
  • Extension Blocking
  • MIME type blocking
  • URL Filter
  • Content Removal
  • SSL Scanning
  • Certificate trust check
  • Certificate date check

After creating the exceptions, I restarted the “Microsoft Azure AD Connect Authentication Agent”. The errors stopped and Azure AD Pass-through started to function correctly! Also the status of the Authentication Agent now reports a status of active.