Category Archives: Security

Authorization to Microsoft Graph: Azure Registered Apps API permissions

Being authenticated to Microsoft 365 tenant means Microsoft 365 knows who is trying to get access. To actually be able read/write or manage resource, your app must be Authorized to this resource.

For details – pls refer to MS authorization and Microsoft Graph API permissions. But again, in short in our case that means we need to have an API permission configured for our azure registered app. There are two kinds of API permissions – delegated and application.

Delegated permissions are intended to allow currently authenticated user to have access to the resource. Effective user permissions in this app would be an intersection of user own permissions and app permissions. So if an app have “Sites.FullControl.All” SharePoint delegated API permissions – that does not mean that user will have full control over all sites.

Application permissions are what it says – once permissions are configured – application will have access to the resources according to API permissions.

Generally, application permissions allow an app to have access to all resources of the same kind in tenant, e.g. to get one specific groups owners an app must have “GroupMember.Read.All” permission that allows an app to read all tenant groups and their members. There are some exceptions – e.g. for Teams Microsoft developed RSC that allows scoped app access. For SharePoint there is a similar option – “Sites.Selected” API permissions.

API permissions must have an Admin consent (see below).


Microsoft 365 admin center: Manage ownerless Microsoft 365 groups and teams

There is a new feature published at Microsoft roadmap site:

Microsoft 365 admin center: Manage ownerless Microsoft 365 groups and teams

Teams, Outlook groups, Team Sites etc. powered by Microsoft 365 Groups supports two roles: members and owners. Members can collaborate with others in the group through files, emails, messages etc. Owners manage the group membership and monitor content and conversations. When employees leave an organization or switch projects internally, it results in their existing user accounts getting deleted. If such employees were group owners, keeping track of their groups becomes critical to ensure accountability within the organization. We have introduced a new ownership governance policy to help automate the management of ownerless groups by requesting active members to become owners of the group. Admins can define who is eligible for these notifications and configure what notifications and how often these notifications are sent to active group members. Users, who are members of the ownerless groups can simply accept or decline request via the actionable email message.

  • Feature ID: 180749
  • Added to roadmap: 10/10/2023
  • Last modified: 10/10/2023
  • Product(s): Microsoft 365 Admin Center
  • Cloud instance(s): GCC
  • Platform(s): Web
  • Release phase(s): General Availability

But based on the feature description – all looks exactly as what we already have for years as “Microsoft 365 ownerless groups policy” which you can configure under Microsoft 365 Admin Center -> Settings -> Org settings -> Microsoft 365 groups

More on Microsoft 365 ownerless groups

Massive Microsoft 365 groups update with PowerShell

What if you need to bulk update Microsoft 365 groups membership e.g. to add a group owner or member for tens of thousands m365 groups? Iterating through groups one-by-one is unproductive and could take days. Can we do it faster? Here is what I found.

In my case, it was Microsoft 365 ownerless groups policy implementation for large tenant… Skipping details – I needed to update ownership for 10,000 Microsoft 365 groups and I was looking for a best/fastest possible option maybe some kind of bulk update or with multiple threads. And I figured out that the fastest way is to use PnP.PowerShell that calls Microsoft Graph API but run it against list of groups with PowerShell parallel trick. Here is the sample PowerShell code:

$groups | ForEach-Object -Parallel {
    $owner = ""
    Add-PnPMicrosoft365GroupOwner -Identity $_.Id -Users $owner
} -ThrottleLimit 50

That worked for me perfectly and it took ~8 seconds per 1,000 groups.

Sites.Selected permissions provisioning automation


You administer Microsoft 365 SharePoint Online. Part of your daily activities is providing Microsoft Graph and SharePoint Sites.Selected API permissions to other users (developers).

In Aug/Sep 2023 Microsoft pushed an update that prevents site collection admins to create or update an Azure Access Control (ACS) principal (that was the way most of developers used to get Client Id and Client secret to access SharePoint site). So your users are probably getting something like Your SharePoint tenant admin doesn’t allow site collection admins to create or update an Azure Access Control (ACS) principal message attempting to create or update SharePoint App-only principal at AppRegNew.aspx or AppInv.aspx pages. Here are more details on the issue.

Microsoft and MVPs shared some technique how to provide Sites.Selected API permissions, but dealing with scripts manually, elevating individual permissions every time you need to run the script – it all takes time and not very efficient. More and more devs are reaching you on the app. So you want to automate this process.


Solution architecture

My way to automate it includes:

  • SharePoint list as a frontend
    here you can accept intake requests, organize approval workflow and display automation results
  • Azure Function App as a backend
    here will be your PowerShell script hosted that runs on scheduled basis and takes care of actual permissions provisioning

Solution details

High-level, getting application permissions to some specific SharePoint site is a two-step process:

  1. get application registration in Azure and properly configure it
  2. get permissions for this application to a specific SharePoint site

For the first step – check this and this articles. I’ll focus on the second step below.

You can provide Sites.Selected permissions for the app to a site with

I will be using second one one. Also PnP.PowerShell will be used to get access to SharePoint intake site and read/update requests from SharePoint list and so on.

Azure App Registration

I registered an admin Application in Azure – “SharePoint Automation App”, added Graph Sites.FullControl.All and SharePoint Sites.FullControl.All permissions, then added Microsoft Graph Directory.Read.All permissions and got tenant admin consent:

I generated a self-signed certificate and added it to the app:

This app will be used to call provide permissions, and to connect to the SharePoint front-end.

Users will register their applications in Azure, add Graph Sites.Selected and SharePoint Sites.Selected permissions, got tenant admin consent, then request permissions to the specific site by creating an intake request – new list item.

Front-End SharePoint Site

I created a SharePoint site for automation. This site will play a front-end role for users. I created a list “Sites.Selected” and updated list columns so I have the following fields:

  • Target Site Url
  • Application Id
  • Permissions (read/write)
  • Automation Output

In real-world (Prod) – You can (should) also implement approval workflow as you’d provide permissions for the application to the site only with this site owner approval. The PowerShell code behind should also validate site owner’s consent with app access to site. But for the sake of simplicity I’ll skip this in my demo.

Azure Function App

I created an Azure Function App with the following parameters:
– Runtime stack: PowerShell Core
– Version: 7.2.
– OS: Windows
– Hosting plan: Consumption

And then PowerShell timer-triggered function in Visual Studio Code.

Function requirements.psd1 (it takes a few hours for Azure to install modules; while modules are installing – you might see “[Warning] The first managed dependency download is in progress, function execution will continue when it’s done. Depending on the content of requirements.psd1, this can take a few minutes. Subsequent function executions will not block and updates will be performed in the background.”):

    'Az' = '10.*'
    'PnP.PowerShell' = '2.*'

Azure Az module to access other Azure resources. PnP.PowerShell module will be used to access SharePoint.

I will keep my admin Azure registered app in a key vault, so need somehow to let the key vault know that this specific app can access this specific credentials. So I enabled system assigned managed Identity for the Function App:

MS: “This resource is registered with Azure Active Directory. The managed identity can be configured to allow access to other resources…”.
I’m going to use an object (principal) Id of this function to grant access to keyvault.

Azure key vault

Surely we do not hard-code app secrets. So we need a key vault o store app credentials.

I created a key vault under the same resource group in Azure and named it “SharePointAutomationDemo”. Then I added a roles assignment – “Key Vault Secret User” and “Key vault Reader” to the Function App via it’s managed identity:

I also assigned “Key Vault Administrator” role to the user (developer) who will add certificates/secrets to this key vault and develop Azure function code.

Code repository


Part 1: Getting Azure App Registration with Sites.Selected API Permissions

Part 2: SharePoint and Microsoft Graph API Sites.Selected permissions provisioning automation

Microsoft 365 ownerless group policy to send more than 10,000 notifications

It is known that a single Microsoft Exchange account is not sending more than 10k emails per day.

It is also know that once activated – Microsoft 365 groups ownerless policy will be sending notifications for all groups in scope to specified number of group members within 24 hours.

The question is: what if there are more than 10,000 notifications to send (e.g. 4,000 ownerless groups and the policy is configured to send notification to 3 members per group – that gives us 12,000 notifications to send)? Would the policy send 10k notifications and the rest 2k notifications the next day?

I’m conducting an experiment. I created 10k groups in my lab tenant with one owner and 3 random members. Then I configured a policy that is sending notification to a 3 most active members (in this case – random members). And then I made all these groups ownerless by deleting the single owner Id from Azure AD (Microsoft Entra).

Here is what I got from users perspective:

useruser groups
got messages
day 1
got messages
day 2
got messages
1 Roger50121374
2 Dick50391349
3 Bob51083412
4 Bapu49081376
5 Stas49961437
6 David49591377

Here is what audit log says:

Events “OwnerlessGroupNotified” day 1: 4949
Events “OwnerlessGroupNotified” day 2: 95
Events “OwnerlessGroupNotified” total: 5044
Each event details says 3 members were notified.

It seems like groups are selected by policy in random order.

Massive E-mails sending was started 43 minutes after midnight UTC

“OwnerlessGroupNotified” were logged at the rate of
1925 events during 1-st hour,
2029 events during 2-nd hour,
785 events during 3-rd hour,
176 events during 4-th hour,
26 events during 5-24 th hour,
95 events during next 25-48 hours
so max rate was one event every 3 seconds in the beginning (or 1 e-mail per second) …


Your SharePoint tenant admin doesn’t allow site collection admins…


You are trying to register an application at SharePoint site with appregnew.aspx page and you are getting an error or notification message “Your SharePoint tenant admin doesn’t allow site collection admins to create an Azure Access Control (ACS) principal“.

Your SharePoint tenant admin doesn't allow site collection admins to create an Azure Access Control (ACS) principal. Please contact your SharePoint tenant administrator

Or you are trying to provide ACS-based permissions for an application to SharePoint site with appinv.aspx page and you are getting “Your SharePoint tenant admin doesn’t allow site collection admins to update app permissions. Please contact your SharePoint administrator.

Your SharePoint tenant admin doesn't allow site collection admins to update app permissions. Please contact your SharePoint tenant administrator

You can still view and even delete your apps permissions from /_layouts/15/appprincipals.aspx page:


This is due to a recent update to Microsoft 365 (tenant governance security measures enhancement MC660075) implemented by Microsoft in Aug/Sep 2023. According to the update, only tenant administrators can create or update ACS service principal by default.

The root cause for this is that the Microsoft is pushing developers out of that legacy ACS-based SharePoint Apps-only service principals towards Azure-registered applications with Sites.Selected API permissions as they are more secure etc.
In Nov 2023 Microsoft announcement retirement of ACS principals.

Key differences between ASC and Sites.Selected are:

ACS-based SharePoint app/permissionsApps registered in Azure with Sites.Selected API permissions
Support authentication with client secret only, Secrets are valid for 1 year exactly.Support authentication with client secret and/or certificate, custom expiration time.
Support granular access to SharePoint site, e.g. to site collection or web (subsite) or a specific list or library.Support only access to entire site collection (but Microsoft says granular access is coming)
Support only classic SharePoint REST API and CSOMSupport both – classic SharePoint REST API and CSOM and Microsoft Graph API
App id (client id) is created via appregnew.aspx at a specific SharePoint site by site collection administrator (disabled in Sep 2023).App id (client id) is created in Azure portal (Entra Id), API Sites.Selected permissions are configured via Azure portal (Entra Id) and require tenant admin consent.
Permissions for the app to a site are provided at the site by site collection administrator via appinv.aspx page (disabled in Sep 2023).Permissions for the App to to a specific SharePoint site are provided via Graph API by SharePoint admin with PowerShell script.

Solution #1 – switch to Sites.Selected

  1. Register an application in Azure (via Entra Id – Azure portal GUI, PowerShell script or your company’s specific helpdesk/servicedesk request)
  2. Update the app so both – MS Graph API Sites.Selected and SharePoint Sites.Selected permissions are configured, then
  3. API permissions must be consented – so you’d seek/request your tenant admin consent
  4. Obtain and upload client certificate (recommended) or generate client secret
    (at this moment you should be able to authenticate to tenant)
  5. Request access for the app to a specific SharePoint site – your SharePoint service admin should be able to do that
    (at this moment you should be able to authorize to your SharePoint site).
  6. Validate your app has access to the target SharePoint site with PowerShell
    (check validation scripts below under References).
  7. Use recommended by Microsoft technique, code samples are available for the most popular languages/platforms – Python, C#, Java etc. (check below under References).
  8. Secure your certificate and/or secret. It is not a good idea to use hard-coded secrets, so consider using special services/storages for secrets (aka Vaults)

If you are hosting your application in Azure – consider using managed identity.

Step-by-step guide with screenshot – how to get app with Sites.Selected permissions

Video guide on using Sites.Selected to access SharePoint as application:

There are 3-rd party (and Microsoft) apps developed using classic approach (examples – Azure data Factory, Alteryx). So in some cases Sites.Selected permissions are not enough to get access to SharePoint.

Solution #2 – admin to register/update an ACS app

This option is acceptable if you have existing application that require ACS-based access.
This option is not recommended for new development, as ACS is deprecated and scheduled for retirement.

Microsoft (MC660075 in Message Center): “site collection admin will be unable to register app or update app permissions through above pages unless authorized explicitly by the SharePoint tenant admin” and “With this update site owners will not be able to register/update apps unless the tenant admin explicitly allows it.”

That is incorrect. Site collection admin cannot register app (appregnew) or provide permissions to the app (appinv) anymore. Tenant admin does not authorize site collection admins. Instead tenant (or SharePoint) admin can register an app or provide permissions to the app at a specific site (not changing the entire default behavior back…). But there was no such option (!) in the middle of October 2023, when this feature was enabled at all tenants. Even having a SharePoint admin or tenant admin permissions – if you tried to register an app with AppRegNew.aspx – you got the same error message “Your SharePoint tenant admin doesn’t allow site collection admins to…”.

Later (Checked today – Nov 6, 2023) it seems like Microsoft has implemented it! E.g. now SharePoint or tenant admin is able to register an app with AppRegNew.aspx or update it with AppInv.aspx at any specific site collection. SharePoint or tenant admin must also be among this site collection admins.

It is ok (and I’d say the preferred way) to provide ACS permissions to the app registered in Azure, so do not register apps in SharePoint anymore (do not use AppRegNew.aspx).

Bottom line: if ACS-based permissions are required for app here you go:

  • register application in Azure (Entra id)
  • activate your SharePoint service/tenant admin role
  • ensure you are also target site collection administrator
  • navigate to the site appinv.aspx page – e.g.
    and us Azure registered app (client) Id. E.g. for lookup provide
    • Azure registered app (client) Id for – click lookup
    • localhost as app domain
    • https://localhost as redirect url
    • Permission Request XML – depending on permissions you need, e.g. for full app access to entire site collection:
<AppPermissionRequests AllowAppOnlyPolicy="true">  
   <AppPermissionRequest Scope="http://sharepoint/content/sitecollection" 
    Right="FullControl" />

Solution #3 – step back (not recommended)

It is possible to switch back this new default behavior that prevents site collection admin to register/update apps at SharePoint. This is done with PowerShell command

Set-SPOTenant -SiteOwnerManageLegacyServicePrincipalEnabled $true

To run this command – you’d need to be a SharePoint service or tenant admin.

But this will be a step back on your journey in improving m365 tenant safety, as after that you’ll have a self-registered service principals out of control again. So devs will be using it not being aware of ACS retirement and when Microsoft switch off ACS – it will be a disaster, as all app will stop working. That is why Microsoft implemented this feature to soft-disable ACS and allowed us 2 years to redesign or apps and migrate from ACS to Entra Id apps with Sites.Selected. So this solution is not recommended.

In case you really need an exception to provide an ACS-based service principal – there is Solution number 2.

Full text of Microsoft’s MC660075 message

(Updated) SharePoint admin control for App registration / update


Message Summary
Updated August 30, 2023: We have updated the content below for clarity. Thank you for your patience.

This is an enhancement to the security measures for administrative governance that modifies the default procedures for SharePoint app registration via AppRegNew.aspx page and permission updates via AppInv.aspx page. Following the implementation of this change, site collection admin will be unable to register app or update app permissions through above pages unless authorized explicitly by the SharePoint tenant admin.

Upon attempting to register an application on AppRegnew.aspx page, a notification will be displayed stating “Your SharePoint tenant admin doesn’t allow site collection admins to create an Azure Access Control (ACS) principal. Please contact your SharePoint tenant administrator.”

Similarly, upon attempting to update app permissions on AppInv.aspx page, a notification will be displayed stating “Your SharePoint tenant admin doesn’t allow site collection admins to update app permissions. Please contact your SharePoint tenant administrator.”

Kindly note that app registration and permission update via Microsoft Azure portal are not impacted by this change.

When this will happen:

The rollout process is scheduled to commence in late August and is expected to conclude in mid-September.

How this will affect your organization:

With this update site owners will not be able to register/update apps unless the tenant admin explicitly allows it.

To modify the default behavior, the tenant administrator must execute the following shell command to explicitly establish the flag as TRUE, thereby superseding the default value of FALSE. The service principal can only be created or updated by the tenant administrator by default. However, when the flag is set to TRUE, both the SharePoint tenant admin and site collection admin will be able to create or update the service principal through SharePoint.

The shell command is: Set-SPOTenant -SiteOwnerManageLegacyServicePrincipalEnabled $true

Note: The property ‘SiteOwnerManageLegacyServicePrincipalEnabled’ becomes visible in tenant settings after SharePoint Online Management shell is updated to 16.0.23710.12000 or a later version. But before this rollout, the value will always be TRUE even explicitly set to FALSE. It will only automatically be switched to FALSE as the default value after the rollout is launched.

What you need to do to prepare:

No proactive measures are required to prepare for this change. Nevertheless, it is advisable to inform your users of this modification and update any relevant documentation as necessary.


SharePoint Sites Lookup

That’s a very common problem in SharePoint world. You are looking for a site owner but there is no tool available for regular user to find who owns the site.


You get a link to some SharePoint site, but you do not have access to it. You requested access but nobody has responded. You need to find who is the site owner.

(To be continued)

PowerShell scripts for Microsoft 365 SharePoint

After many years working with SharePoint I wrote a lot of PowerShell scripts that help me support, troubleshoot, administer and secure SharePoint. So I’m sharing my scripts with you.

It’s here: