Modern SharePoint authentication in Azure Automation (Runbook) with PnP PowerShell

Modern SharePoint authentication in Azure Automation (Runbook) with PnP PowerShell

Modern authentication (not only) in SharePoint Online becomes more and more relevant as more and more organizations turn off LegacyAuthentication. In fact this means the classic Credential authentication with UserName and Password does not work anymore.

The issue is, when connecting with SharePoint Designer or PowerShell with classic credentials you will receive a “Cannot contact web site  or the web site does not support SharePoint Online credentials” error.

The setting that handles this is the following:

Connect-SPOService -Url "https://<Your-Tenant>-admin.sharepoint.com"

$tenantsettings = Get-SPOTenant

$tenantsettings.LegacyAuthProtocolsEnabled

If this setting is False you cannot login with classic credentials. To change this you could run

Set-SPOTenant -LegacyAuthProtocolsEnabled $true
But for security reasons your organization might think different.

For Microsoft.Online.SharePoint.PowerShell the story ends here for now as it does not work with modern authentication especially in an unattended mode such as Azure Automation runbooks.

Luckily the more popular PowerShell module in case of SharePoint Online is PnP-PowerShell. This module provides capabilities for an unattended authentication towards SharePoint Online. In this blogpost I will show you how to handle this inside an Azure Automation runbook.

According to Microsoft’s PnP documentation for an app only permission authentication you would need the following things to get this scenario up and running. I will show you each of them and point out the “Azure Automation specifics”.

 

Create a self-signed certificate

Here you can either use a script or (much simpler) the new New-PnPAzureCertificate cmdlet. For instance run the following:

$Password = "******"
$secPassword = ConvertTo-SecureString -String $Password -AsPlainText -Force
$cert = New-PnPAzureCertificate -Out "AzureAutomationSPOAccess.pfx" - `
 -ValidYears 10 `
 -CertificatePassword $secPassword
 -CommonName "AzureAutomationSPOAccess" `
 -Country "DE" `
 -State "Bavaria"

This would create a self-signed certificate with the needed values and, enforced by the “-out” parameter, write it to a .pfx file in the current directory.

After that simply run the following command and keep the window open. We would need the JSON result (shortened here) a in a minute.

$cert.KeyCredentials

{
    "customKeyIdentifier": "zUFQhchR6FJ0...",
    "keyId": "4d2fe8fc-0dbb-45a7-...",
    "type": "AsymmetricX509Cert",
    "usage": "Verify",
    "value":  "MIIDJDCCAgygAwIBAgIQV9qo..."
}

Register an Application

The next thing would be to register an app in your Office 365 Azure AD. Simply go to your Office 365 Admin Center and from there down below on the left side under “Admin Centers” to the “Azure Active Directory” admin center.

Here I encourage you now to use the new “App registrations (preview)” version and register an application.

RegisterApp1

Here only the “Name” is really relevant for us. Once you have that, you would need to give permissions to that app registration.

RegisterApp2_Permissions

Assuming you want to create lots of runbooks with several admin scenarios the selected permissions would be necessary. If you only have specific needs you might reduce it to a lower level. Pay attention to check “Application permissions” as we cannot handle a delegated scenario.

RegisterApp3_GrantPermissions

Anyway, any given SharePoint permission needs an administrator consent. Simply click the button but make sure you are a tenant administrator.

RegisterApp4_Granted

Then your permissions should be granted.

Next we would need to add our “KeyCredentials”. This “relates” our app registration to the recently created certificate. So switch back to our left open PowerShell window and copy the JSON output. Then switch to the app registration’s manifest and insert it there inside the [] .
At the moment of writing there was an issue with the “Preview” version of the App registration. If you receive the error “Failed to update application SPAccess. Error details: KeyValue cannot be null or empty” you can simply re-open your app registration in the classic mode, insert it there and save. Switch back to the preview mode and there are even more parameters now:

RegisterApp5_Manifest

The final thing would be to copy the App Id. Therefore switch to the “Overview” tab. Here you can copy the ID to the clipboard once we need it in another minute.

RegisterApp6_CopyID

Automation Account settings

PnP PowerShell module

I assume you already have an Automation Account configured. If not follow the documentation from Microsoft. On top you should install the PnP PowerShell module under modules. Simply install it on your local machine and then ZIP the local folder “C:\Program Files\WindowsPowerShell\Modules\SharePointPnPPowerShellOnline” and upload it under “Modules” in your Automation Account.

Upload pfx certificate

Now under “Certificates” upload your recently created certificate (the .pfx file). Therefore you would need the given name and the password.

AzureAutomation1_AddCert

Pay attention to check “Yes” for Exportable as we later need exactly this capability!

Finally I would like to store our App ID as well as the password for the certificate inside the Azure Automation Account assets. Although both values do not exactly belong together, you can store them as a simple credential pair. We later use them independently.

AzureAutomation1_AddCredentials

The Runbook – PnP PowerShell Commands

Now we have everything in place to create our first runbook with modern app only authentication. Therefore create a new PowerShell runbook and insert the following code:

$azureSPOcreds = Get-AutomationPSCredential -Name 'AzureAutomationSPO'

$siteUrl = "https://.sharepoint.com/teams/MMTeamNo1"

$aadDomain = ".onmicrosoft.com"

$Password = $azureSPOcreds.GetNetworkCredential().Password

$secPassword = $azureSPOcreds.Password

$clientID = $azureSPOcreds.UserName

$cert = Get-AutomationCertificate -Name 'AzureAutomationSPOAccess'

$pfxCert = $cert.Export(3 ,$Password) # 3=Pfx

$certPath = Join-Path "C:\Users" "SPSiteModification.pfx"

Set-Content -Value $pfxCert -Path $certPath -Force -Encoding Byte 
    

if (Test-Path $certPath)

{

    $pnpCert = Get-PnPAzureCertificate -CertificatePassword $secPassword `
					-CertificatePath $certPath

    Write-Output "Connecting to $siteUrl"

    Connect-PnPOnline   -CertificatePath $certPath `

                        -CertificatePassword $secPassword `

                        -Tenant $aadDomain `

                        -ClientId $clientID `

                        -Url $siteUrl 

    $web = Get-PnPWeb

    Write-Output $web.Title

}

else

{

    Write-Output "No Cert"

}

For simplicity reasons I put some other values in as hardcoded which you would also put to different Automation variables (or ONE as a config XML).

The first interesting thing is getting the $azureSPOcreds. After retrieval we extract the UserName on the one hand, that is our AppID. On the other hand with two commands we extract the password, once simply as a SecureString by retrieveng the Password attribute and give it to the $secPassword variable. Then with the help of the GetNetworkCredential() method we also extract the password in PlainText (!!!) and give it to the $Password variable. We need it that way for the certificate.

But here you see a disadvantage of the Azure Automation assets. Once you have some Admin credentials in there AND access to it, you also have the clear text password! 😉 

The next trick we use is to export the certificate to the “local filesystem of the Automation account” which is only valid during runtime of a runbook execution.

This is because the Connect-PnpOnline command we use next expects it that way and cannot handle a X509Certificate2 object directly (that is what we get with the Get-AutomationCertificate cmdlet).

Once we have that exported we simply ‘Test-Path’ our export and if everything is fine we can Connect-PnPOnline to our SharePoint and execute a simple demo task to get the current web’s title.

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