Skip to main content

Modifying your Exchange Online PowerShell Managed Code to use oAuth and MSAL

While not as popular these days many .net developers may have in the past used Managed code to run Exchange Online PowerShell cmdlets to do things like assign Mailbox Permissions or run other EXO PowerShell Cmdlets to get reporting information where no other alternatives where available (or are still available). The majority of these code bases are most likely using basic authentication using something like


In this post I'm going to cover how to change your existing code, you might want to consider however making use of some of the new ExchangeV2 Powershell module functionality to improve performance and security . But to migrate existing code to use oAuth from Basic Authentication is relatively straight forward
  1. You will need some code to do the Authentication, for this I'm going to use the MSAL library because its both the recommended library from Microsoft and its easy to use. 
  2. You should create your own Azure App registration and consent to it that has the Exchange.Manage Permissions eg


(If you can't create your own app registration you can use the well-known ClientId from the V2 PowerShell Module which I've used in the below samples).

Once you have your authentication code generating a Token you then use that as the Password in the PSCrednetial object you pass in the WSManConnectionInfo object. The one thing you need to change is the WSManConnection URI to include the parameters DelegatedOrg which should be set to your domain and add  BasicAuthToOAuthConversion=true eg so your connection string should look like
https://outlook.office365.com/powershell-liveid?DelegatedOrg=youdomain.onmicrosoft.com&BasicAuthToOAuthConversion=true
eg an Interactive Auth sample to run Get-Mailbox would look like 

If you need your code to run non-interactively with a set of credentials you can use the ROPC grant like

 



Popular posts from this blog

The MailboxConcurrency limit and using Batching in the Microsoft Graph API

If your getting an error such as Application is over its MailboxConcurrency limit while using the Microsoft Graph API this post may help you understand why. Background   The Mailbox  concurrency limit when your using the Graph API is 4 as per https://docs.microsoft.com/en-us/graph/throttling#outlook-service-limits . This is evaluated for each app ID and mailbox combination so this means you can have different apps running under the same credentials and the poor behavior of one won't cause the other to be throttled. If you compared that to EWS you could have up to 27 concurrent connections but they are shared across all apps on a first come first served basis. Batching Batching in the Graph API is a way of combining multiple requests into a single HTTP request. Batching in the Exchange Mail API's EWS and MAPI has been around for a long time and its common, for email Apps to process large numbers of smaller items for a variety of reasons.  Batching in the Gr...

Exporting and Uploading Mailbox Items using Exchange Web Services using the new ExportItems and UploadItems operations in Exchange 2010 SP1

Two new EWS Operations ExportItems and UploadItems where introduced in Exchange 2010 SP1 that allowed you to do a number of useful things that where previously not possible using Exchange Web Services. Any object that Exchange stores is basically a collection of properties for example a message object is a collection of Message properties, Recipient properties and Attachment properties with a few meta properties that describe the underlying storage thrown in. Normally when using EWS you can access these properties in a number of a ways eg one example is using the strongly type objects such as emailmessage that presents the underlying properties in an intuitive way that's easy to use. Another way is using Extended Properties to access the underlying properties directly. However previously in EWS there was no method to access every property of a message hence there is no way to export or import an item and maintain full fidelity of every property on that item (you could export the...

EWS Create Mailbox folder Powershell module for Exchange and Office365 Mailboxes

This is a rollup post for a couple of scripts I've posted in the past for creating folders using EWS in an Exchange OnPremise or Exchange online Cloud mailbox. It can do the following Create a Folder in the Root of the Mailbox Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test Create a Folder as a SubFolder of the Inbox Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Inbox' Create a Folder as a SubFolder of the Inbox using EWS Impersonation Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Inbox' -useImpersonation Create a new Contacts Folder as a SubFolder of the Mailboxes Contacts Folder Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -ParentFolder '\Contacts' -FolderClass IPF.Contact Create a new Calendar Folder as a SubFolder of the Mailboxes Calendar Folder Create-Folder -Mailboxname mailbox@domain.com -NewFolderName test -Parent...
All sample scripts and source code is provided by for illustrative purposes only. All examples are untested in different environments and therefore, I cannot guarantee or imply reliability, serviceability, or function of these programs.

All code contained herein is provided to you "AS IS" without any warranties of any kind. The implied warranties of non-infringement, merchantability and fitness for a particular purpose are expressly disclaimed.