Teams PowerShell Module - Certificate Authentication

There are several ways to get the Teams PowerShell module to authenticate against Azure in order to get access to running Teams PowerShell in your Tenancy. Most people will be used to using the interactive method, where you just run the basic Connect-MicrosoftTeams command and get an interactive Azure auth screen that pops up and you enter your user account details into. This is fine if you are manually connecting and doing this by hand. However, what if you want to run an Azure Function that needs to authenticate automatically each time it executes? Well, for that you want to use an application authentication method.

Currently as of the module version 4.9.1, Microsoft officially supports two methods for application authentication when connecting to the Teams PowerShell module:

• Certificate based authentication – In this method you have a certificate with private and public keys. The PC connecting to Azure needs to have a copy of the private key and Azure needs to have a stored copy of the public key. As part of the connection the private key will be used to sign the connection and if Azure can decrypt the information with the public key then the PC is trusted to connect. This essentially makes the private key like a password that you need to ensure that no one else has access to.
• Token based authentication – The token-based method requires that you set up a Client Secret in Azure. When you connect to Azure using the PowerShell module, you authenticate against the Token Service using the Client Secret and get Tokens back that you can use to connect to the service. In the case of the Teams module, you need to get two tokens to be able to run all the commands. You can find out more about this option here: Token Auth Post

In this post we are going to focus on the certificate-based authentication method. Here are the steps for setting up and connecting using certificate-based authentication:

 

Step 1: Generate a Certificate:

The good news here is that the certificate you need does not need to be signed by an internet-based Certificate Authority. You can simply create a self-signed certificate on a PC and use this for connection. Below is a PowerShell command you can run (you must run the PowerShell window as Administrator to execute it). The most important flag in the command is the KeySpec flag which tells it to generate a certificate that can be used for Key Exchange.

New-SelfSignedCertificate -certstorelocation cert:\localmachine\my -Subject TeamsAppTestCertificate01 -KeySpec KeyExchange

 

Step 2: Export the Certificate:

In order to export the certificate you can either run PowerShell or do it by hand with the Certificate Snap-in. Both options will be detailed below. Choose the one that you’re most comfortable with.

Export the Private Key (This step is only needed if you want to run PowerShell from a different machine that you have created the certificate on, for example, a Function App, etc):

PowerShell:

$password = ConvertTo-SecureString -String "SpecialPassword123!" -Force –AsPlainText

Export-PfxCertificate -Cert "cert:\LocalMachine\My\8E4CKSHDUSG873F66D99AC7935F53" -FilePath "C:\temp\AuthPrivateKey.pfx" -Password $password

Note: The thumbprint to be used here will be output from the New-SelfSignedCertificate command you previously ran.

 

Or Windows UI:

Once again, this is is only needed if you want to run PowerShell from a different machine that you have created the certificate on, for example, a Function App, etc.

Search PC for mmc.exe > File Menu > Add or Remove Snap-in > Certificates > Add > Computer Account > Personal > Certificates Folder > Right Click on the Certificate > Export…

Export Certificate Wizard:

Click Next...

Select: "Yes, export the private key":

Go with the default export options:

Enter a password for the PFX file and ensure that you select TripleDES-SHA1 (I have found that importing on some platforms is not supported with AES):

Enter a name and location for the pfx file to be output to:

Export the Public Key (to be uploaded to the App Registration in Azure)

PowerShell:

Export-Certificate -Cert "Cert:\LocalMachine\My\8E4CKSHDUSG873F66D99AC7935F53" -FilePath "C:\temp\AuthPublicKey.cer"

Or Windows UI:

Click Next... 

Do not export private key:

Select the format of the file (DER is okay in this case) and click next:

Select the name of the file and click next:

Step 3: Configure the App Registration:

Open the Azure AD Portal and select the Azure Active Directory > App Registration section:

 Click the "New Registration" Button:

 

Fill in a name for the application and click the Register button:

The App Registration will now be created, however, there is still more config to do:

Go to the “Certificates & secrets” blade:

Select the location of the public key certificate that you exported earlier. Add a description and click OK:

The certificate should now show up in the certificates area:

Now open the API Permissions tab within the App Registration, Click "Add a permission":

You will need to add the following Graph API permissions to the App Registration:

User.Read.All

Group.ReadWrite.All

AppCatalog.ReadWrite.All

TeamSettings.ReadWrite.All

Channel.Delete.All

ChannelSettings.ReadWrite.All

ChannelMember.ReadWrite.All

These permissions are documented by Microsoft here, so you may want to check to see if there have been any updates for the PowerShell version you're using: https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-application-authentication

Click the "Microsoft Graph" option:

Select "Application Permissions":

Select the permissions that were listed above:

Ensure that you have added all the permissions. If you missed any then repeat the above steps for all the permissions in the list…

 

After adding all the permissions, you need to click the “Grant admin consent for <tenant id>” button on the main Permissions screen:

At the end of this procedure, you should have the following permissions all assigned with admin consent granted:

In a final twist in this adventure, you also need to make sure you assign Teams Administrator privileges to the App Registration in order for it to be able to run CS commands. You do this by going to the Active Directory tab > Roles and Administrators > Teams Administrator Role:

 

Assign the Service Permission that is named the same as your App Registration to the RBAC Role:

Connecting To Teams PowerShell

 

Now that all the backend work has been done we can get down to doing some connecting. When you connect it needs to be from a machine that has access to the certificate. On a PC this means it has to be in the certificate store. If it’s from a machine in Azure there are various methods for doing this too (which I may well get to in another post…).

You will need to know the ApplicationId that was given to the App Registration in Azure. You can find this out by looking going to the Overview tab and looking for the GUID that has the title “Application (client) ID”. The TenantId is the base domain name that was first given to your tenancy when it was created or alternatively can be the GUID that’s in the Overview tab named as “Directory (tenant) ID” (both options will work).

 

Teams Module Connect Command:

Connect-MicrosoftTeams -CertificateThumbprint "3ab0e057bc3278ecb2a33123042e5a7a8001ff8c" -ApplicationId "319d0a47-9a48-45b0-b416-14aca00e7ece" -TenantId contoso.onmicrosoft.com

 

When connection is successful, you’ll get back an object displayed in the PowerShell window that tells you the Account, Environment, Tenant and TenantId values. From here you should be able to run almost all of the commands from the module, with the following exclusions:

As of 4.9.1; All cmdlets are supported now, except for the cmdlets mentioned below:

• New-Team
• [Get|Set|New|Sync]-CsOnlineApplicationInstance
• *-CsUserCallingSettings
• *-CsUserCallingDelegate
• *PolicyPackage*
• *-CsTeamsShiftsConnection*
• *-CsBatchTeamsDeployment*

  

The Wrap Up

 

Congratulations, you’re now an expert at certificate-based authentication with the Teams PowerShell module. If you are interested in Token Based Authentication using the Teams Module, then you can check out my post on that over here: Token Auth Post.

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Teams PowerShell Module – Token Authentication

There are several ways to get the Teams PowerShell module to authenticate against Azure in order to get access to running Teams PowerShell in your Tenancy. Most people will be used to using the interactive method where you just run the basic Connect-MicrosoftTeams command and get an interactive Azure auth screen that pops up and you enter your user account details into. This is fine if you are manually connecting and doing this by hand. However, what if you want to run an Azure Function that needs to authenticate automatically each time it executes? Well, for that you want to use an application authentication method.

Currently as of the module version 4.9.1, Microsoft officially supports two methods for application authentication when connecting to the Teams PowerShell module:

• Token based authentication – The token-based method requires that you set up a Client Secret in Azure. When you connect to Azure using the PowerShell module, you authenticate against the Token Service using the Client Secret and get Tokens back that you can use to connect to the service. We will dig further into this method in this post.
• Certificate based authentication – In this method you have a certificate with private and public keys. The PC connecting to Azure needs to have a copy of the private key and Azure needs to have a stored copy of the public key. As part of the connection, the private key will be used to sign the connection and if Azure can decrypt the information with the public key, then the PC is trusted to connect. This essentially makes the private key like a password that you need to ensure that no one else has access to. If you would like to know more about this method, please check out my post here about it: Certificate Auth Post.

In this post we are going to focus on the token-based authentication method. Here are the steps for setting up and connecting using token-based authentication:

 

Step 1: Configure the App Registration:

Open the Azure AD Portal and select the Azure Active Directory > App Registration section:

 

Click the New Registration Button:

 

Fill in a name for the application and click the Register button:

 The App Registration will now be created. However, there is still more config to do:

Go to the “Certificates & secrets” blade:

Enter a name for your client secret that makes sense for you and click "Add":

You will now seen your new Client Secret. Copy the secret value and put it somewhere safe:

I'll say it again, before leaving this screen take a copy of the Client Secret Value because it will not be available when you return later. Also, it’s important that you treat this secret as you would a password because it can give anyone the keys to your Teams castle… which would be very bad.

 

Configure the Application Permissions:

You will need to add the following Graph API permissions to the App Registration:

User.Read.All

Group.ReadWrite.All

AppCatalog.ReadWrite.All

TeamSettings.ReadWrite.All

Channel.Delete.All

ChannelSettings.ReadWrite.All

ChannelMember.ReadWrite.All

These permissions are documented by Microsoft here, so you may want to check to see if there have been any updates for the PowerShell version you're using: https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-application-authentication

 

Click the "Microsoft Graph" option:

Select "Application Permissions":

Select the permissions that were listed above:

Ensure that you have added all the permissions. If you missed any then repeat the above steps for all the permissions in the list…

 

After adding all the permissions you need to click the “Grant admin consent for <tenant id>” button on the main Permissions screen:

At the end of this procedure you should have the following permissions all assigned with admin consent granted:

 

In a final twist in this adventure, you also need to make sure you assign Teams Administrator privileges to the App Registration in order for it to be able to run CS commands. You do this by going to the Active Directory tab > Roles and Administrators > Teams Administrator Role:

 

Assign the Service Permission that is named the same as your App Registration to the RBAC Role:

 

Connecting To Teams PowerShell

 

Now that all the backend work has been done, we can get down to doing some connecting.

You will need to know the ApplicationId that was given to the App Registration in Azure. You can find this out by looking going to the Overview tab and looking for the GUID that has the title “Application (client) ID”. The TenantId is the base domain name that was first given to your tenancy when it was created or alternatively can be the GUID that’s in the Overview tab named as “Directory (tenant) ID” (both options will work). And you need to know the Client Secret that was created at the beginning of the App Registration creation process (I did tell you to take note of this -- if you didn’t then you may not be able to see the secret in the portal anymore. If so, then you need to create a new one).

  

The Connection PowerShell:

$ClientSecret   = "P_1a3~cNhA1Jd~iS9.mdUh2ffe_qp~u9Leuk4aYa" # Your Client Secret

$ApplicationID = "00000000-0000-0000-0000-000000000000" #Your Application ID

$TenantID = "YYYYYYYY-YYYY-YYYY-YYYY-YYYYYYYYYYYY" #Your Tenant ID

 

$graphtokenBody = @{  

   Grant_Type    = "client_credentials"  

   Scope         = "https://graph.microsoft.com/.default"  

   Client_Id     = $ApplicationID  

   Client_Secret = $ClientSecret  

} 

 

$graphToken = Invoke-RestMethod -Uri "https://login.microsoftonline.com/$TenantID/oauth2/v2.0/token" -Method POST -Body $graphtokenBody | Select-Object -ExpandProperty Access_Token

 

$teamstokenBody = @{  

   Grant_Type    = "client_credentials"  

   Scope         = "48ac35b8-9aa8-4d74-927d-1f4a14a0b239/.default"

   Client_Id     = $ApplicationID  

   Client_Secret = $ClientSecret

}

 

$teamsToken = Invoke-RestMethod -Uri "https://login.microsoftonline.com/$TenantID/oauth2/v2.0/token" -Method POST -Body $teamstokenBody | Select-Object -ExpandProperty Access_Token

 

Connect-MicrosoftTeams -AccessTokens @("$graphToken", "$teamsToken")

 

I know what you’re thinking… That’s a lot of PowerShell code to just connect to PowerShell and you are correct in thinking that. However, this code, while looking ominous, is actually not all that complicated when you break it down.

Let’s break it down; The first 3 lines are variables where you need to fill in your specific Secret, Application ID and Tenant ID. These are the only three lines that you need to edit, so you can relax. The other lines of code basically run two separate REST calls to Azure to get access to two different tokens. One token is for the Graph API and the other is for Teams. Once you have these tokens you then pass them to the Connect-MicrosoftTeams command which uses them to authenticate against the service.

Note: The tokens have a lifetime of 1 hour, so if you were going to make an app that was going to make a lot of connections over the course of an hour you make want to cache the tokens and reuse them.

When connection is successful, you’ll get back an object displayed in the PowerShell window that tells you the Account, Environment, Tenant and TenantId values. From here you should be able to run almost all of the commands from the module, with the following exclusions:

As of 4.9.1; All cmdlets are supported now, except for the cmdlets mentioned below:

• New-Team
• [Get|Set|New|Sync]-CsOnlineApplicationInstance
• *-CsUserCallingSettings
• *-CsUserCallingDelegate
• *PolicyPackage*
• *-CsTeamsShiftsConnection*
• *-CsBatchTeamsDeployment*

The Wrap Up

 

There’s all you should hopefully need to know about setting up a simple Token Authentication based connect to Microsoft Teams PowerShell. At the beginning of the post I also mentioned Certificate-based authentication. If you would like to know more about Certificate-based authentication, don’t forget you can check out my post here about it: Certificate Auth Post.

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Teams PowerShell Certificate or Token Based Auth WinRM Error

I ran into an issue the other day that was difficult to troubleshoot due to the obscure error that arose. The scenario: I was attempting to use Certificate or Token based Authentication to do an application-based authentication with Azure (instead of the regular interactive password based authentication).

After setting everything up and connecting to Teams PowerShell, there was a persistent error any time a Skype for Business *Cs* command was run. The error referenced the WinRM client not being able to process the request. Here’s the error in question:

PowerShell Error:

PS C:\> Connect-MicrosoftTeams -CertificateThumbprint "897a047bc435843b2a32126544e5a7a8001fee8c" -ApplicationId "216d0455-8988-45b0-b425-222ca02e8ede" -TenantId contoso.onmicrosoft.com

 

Account                              Environment Tenant                               TenantId

-------                              ----------- ------                               --------

219d0455-8988-45b0-b425-222ca01e8ece AzureCloud  6364a50-c3d7-4eee-834c-21a2371df363 6364a50-c3d7-4eee-834c-21a237...

PS C:\> Get-CsOnlineUser

2022-11-22T23:02:46Z [Error] ERROR: Connecting to remote server api.interfaces.records.teams.microsoft.com failed with the following error message : The WinRM client cannot process the request. The authentication mechanism requested by the client is not supported by the server or unencrypted traffic is disabled in the service configuration. Verify the unencrypted traffic setting in the service configuration or specify one of the authentication mechanisms supported by the server. To use Kerberos, specify the computer name as the remote destination. Also verify that the client computer and the destination computer are joined to a domain. To use Basic, specify the computer name as the remote destination, specify Basic authentication and provide user name and password. Possible authentication mechanisms reported by server: For more information, see the about_Remote_Troubleshooting Help topic.

 

From the error it seemed like an issue on the client side to do with the method being used to authenticate or communicate with the cloud endpoint on the client side… However, after exhaustively chasing down anything to do with the client side WinRM settings, nothing was working… This was on the latest 4.9.1 Teams PowerShell module which in its release notes listed application authentication as being made GA (https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-release-notes). As a result, it’s not likely there was a bug in the module that meant that all *CS* commands just didn’t work...

At this point I looked to the cloud. When configuring application-based authentication for the Teams PowerShell module, you need to set up an App Registration and assign it permissions and RBAC roles to allow it to access Teams. In the deployment I was working on, the following permissions were assigned:

 

The documentation (https://learn.microsoft.com/en-us/microsoftteams/teams-powershell-application-authentication) from Microsoft says that the following settings were required:

User.Read.All

Group.ReadWrite.All

AppCatalog.ReadWrite.All

TeamSettings.ReadWrite.All

Channel.Delete.All

ChannelSettings.ReadWrite.All

ChannelMember.ReadWrite.All

Note: For the record, you also need to assign the Teams Administrator RBAC role to the Application Service Principal in the Roles and Administrators area (but this wasn’t the issue in this case).

It appears that all of these permissions were included. So it should be fine, right?

….Wrong.

What I found out was that the “Skype and Teams Tenant Admin API” permissions that were included here were to blame for the error. After removing and revoking both of the innocuous “Skype and Teams Tenant Admin API” permissions, I was able to connect and run *CS* commands to my heart's desire…

So to anyone who says “you can never have too many permissions” it appears that you actually can... 

Note: There may be other permissions that also cause this to happen, so make sure you haven't assigned more permissions than are required.

The Solution

Remove the offending “Skype and Teams Tenant Admin API” permissions:

Once removed, the permissions get demoted into the "Other permissions granted for <tenant name>" area, where you need to then "Revoke all admin consents" before they will be fully removed:

After this you should have these permissions left:

After this, you shouldn't get the WinRM error anymore when running CS commands! 

Be sure that you have applied the Teams Administrator RBAC role to the App Registration Service Principal as well. Go to: Azure Active Directory > Roles and administrators > Teams Administrator > Add Assignments Button > Search for your App Registration Name and assign it:

 

The Wrap Up

I hope that helped out a few of you poor people banging your head against the wall about the WinRM error situation. If you want to check out a full walk through of setting up Certificate or Token based Authentication with the Teams PowerShell Module, check out these posts:

Certificate-based Authentication post

Token-based Authentication post

See ya next time!

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