Automation, EntraID, Identity, M365Permissions, Powershell

Categorizing Service Principals in Entra

12/09/2025 JosL Leave a comment

For M365Permissions I wanted to categorize service principals in an actually useful way.

This is what I came up with so far

    function get-servicePrincipalType{
        Param(
            [Parameter(Mandatory=$true)][object]$spn
        )

        #managed identities are simple :)
        if($spn.servicePrincipalType -eq "ManagedIdentity"){
            return "ManagedIdentity"
        }        

        #other SPN's can be hosted by us, by Microsoft or by a third party 
        #Although 9188040d-6c67-4c5b-b112-36a304b66dad is also officially Msft, it contains consumer apps not built or vetted by Microsoft thus we treat it as third party
        if($spn.appOwnerOrganizationId -in ("f8cdef31-a31e-4b4a-93e4-5f571e91255a","72f988bf-86f1-41af-91ab-2d7cd011db47","7579c9b7-9fa5-4860-b7ac-742d42053c54")){
            return "MicrosoftApplication"
        }elseif($spn.appOwnerOrganizationId -eq &lt;YOURTENANTID>){
            #this is either a homebrew app or an AI agentic app
            if($spn.tags -and ($spn.tags -contains "AgenticApp" -or $spn.tags -contains "AIAgentBuilder")){
                return "AiAgent"
            }else{
                return "InHouseApplication"
            }
        }else{
            return "ThirdPartyApplication"
        }              
    }

Automation, EntraID, Powershell, Security

Function to Spot ALL All-User and All-Guest Groups in Entra ID

29/08/2025 JosL 1 Comment

There are probably many scenario’s where you’d like to identify which Entra groups contain ‘all users’, ‘all guests’ or a combination (all members+all guests).

In my case, I want to use this in M365Permissions, but also needed it for a Maester test to be more precise. It had to be language and implementation agnostic.

M365Permissions uses this mainly for reports that look at oversharing (e.g. when securing a tenant or implementing copilot). But this could also be useful for red/blue teams or any other tenant analysis tooling.

In M365Permissions, I initially looked at the dynamic rule itself, but this is unreliable. Dynamic rules can contain many additional components and can be ordered or written in many ways or the group may have been created without a dynamic rule through e.g. automation.

So I decided to use another approach!

Just get all tenant users from Graph (counts per type).

Then for a given group, look if it matches one of those counts and return a type. Of course, casting members to users to avoid counting devices and looking up membership recursively 🙂

Function: https://github.com/jflieben/assortedFunctionsV2/blob/main/Get-EntraDynamicGroupType.ps1

Azure, M365Permissions

Azure VM Spot Pricing API

15/08/2025 JosL 1 Comment

The Azure Retail Prices API does not give correct prices for SPOT VM’s (which can change at any time).

As I use SPOT VM’s a lot to scan largers tenants with M365Permissions to avoid throttling and get results FAST, I needed a reliable way to get the lowest priced F-series VM to temporarily finish a scan queue before getting discarded again.

I created an initial function using the ‘hidden’ retail billing API which calls the ‘https://s2.billing.ext.azure.com/api/Billing/Subscription/GetSpecsCosts?SpotPricing=true’ endpoint.

My post on Linked then got some advice Morten which I now finally got around into creating a function for, using an official instead of ‘hidden’ API!

This resulted in the Get-VmSpotPrices function, which I’m sharing for free through Github:

https://github.com/jflieben/assortedFunctionsV2/blob/main/Get-VmSpotPrices.ps1

M365Permissions, Powershell

Converting onedrive url to UPN

30/06/2025 JosL Leave a comment

Had a bit of a struggle converting onedrive for business url’s reliably to UPN’s.

Since a path might contain /personal/ multiple times, and we have those pesky national tenants with special url’s to deal with…

So thought I’d share:

function Get-UPNFromOnedriveUrl{
    Param(
        [string]$url
    )

    $userName = ''
    if ($url -match ':\/\/.*?\..*?\/personal\/(.*?)\/') {
        $userName = $matches[1]
    }else {
        Throw "Invalid OneDrive URL format: $url"
    }

    if(!$global:tenantODStyleDomains){
        $global:tenantODStyleDomains = New-GraphQuery -Uri "https://graph.microsoft.com/v1.0/domains" -Method GET -resource "https://graph.microsoft.com" | ForEach-Object { $_.id.replace(".","_") }
    }

    foreach($tenantODStyleDomain in $global:tenantODStyleDomains){
        if($userName -like "*_$tenantODStyleDomain"){
            $prefix = $userName.Replace("$tenantODStyleDomain","") 
            $suffix = $tenantODStyleDomain.Replace("_",".")
            break
        }
    }

    return "$prefix@$suffix".Replace("_","").ToLower()
}

OneDriveMapper, Powershell