Announcing OAuth 2.0 Client Credentials Flow support for POP and IMAP protocols in Exchange Online

AtifMunir

Here is example for IMAP, but the authentication part is the same for POP/IMAP:

https://github.com/DanijelkMSFT/ThisandThat/blob/main/Get-IMAPAccessToken.ps1

scope should be: https://outlook.office365.com/.default

It's in PowerShell, it should be easy to rewrite it in C#.

Authentication part is handled in MSAL.PS but could be rewritten to not use it.

This is replacement for MSAL.PS:

$clientID = "<client id>"
$tenantID = "<tenant id>"
$clientsecret = "<client secret>"

$RequestBody = @{
client_id = $clientId;
client_secret = $clientSecret;
grant_type="client_credentials";
scope="https://outlook.office365.com/.default";
}
$OAuthResponse = Invoke-RestMethod -Method Post -Uri https://login.microsoftonline.com/$tenantId/oauth2/v2.0/token -Body $RequestBody
$AccessToken = $OAuthResponse.access_token

# pre-requirement
# MSAL.PS - https://www.powershellgallery.com/packages/MSAL.PS/4.2.1.3
# code written in MSAL.PS
$SecuredclientSecret = ConvertTo-SecureString $clientsecret -AsPlainText -Force
$ClientApplication = New-MsalClientApplication -ClientId $clientID -TenantId $tenantID -ClientSecret $SecuredclientSecret

$MsalToken = $ClientApplication | Get-MsalToken -Scopes 'https://outlook.office365.com/.default'
$AccessToken = $MsalToken.accessToken