Harden Your Azure Service Principal Role with AutoMonX

It’s easy to get caught up in the excitement of setting up full-scale Azure monitoring with the AutoMonX Sensor Pack for Azure. Auto-discovery works like magic, metrics flow into PRTG effortlessly, and your dashboards come alive. But one key security piece is often overlooked: how secure is the Azure user (service principal) you’re using for monitoring?

If you’re using a service principal with full Reader rights or worse - broad access across your entire subscription, you may be giving away more access than necessary. Good monitoring doesn’t mean insecure monitoring. In this post, we’ll walk you through setting up a secure, scoped Azure monitoring identity using AutoMonX and a custom least-privilege role.

Azure Role security with AutoMonX

The Problem with Over-Permissioned Readers

The default 'Reader' role is convenient. It gives you full read access to every resource in Azure—but that’s also the problem. This includes read access to sensitive resources like:

• VPN gateways

• Network connections

• Key Vaults

• Certificates

This opens the door to unnecessary exposure and potential lateral movement in the event of a compromise.

Introducing the Minimal Monitoring Reader for the Azure Service Principal

AutoMonX recommends and provides a secure role template: the Minimal Monitoring Reader. This custom Azure RBAC role grants only the exact permissions required for the Azure Sensor Pack to function correctly—nothing more.

Key permissions include:

• Microsoft.Insights/metrics/read

• Microsoft.Compute/virtualMachines/instanceView/read

• Microsoft.OperationalInsights/workspaces/query/read

• Microsoft.ContainerService/managedClusters/read

• Microsoft.Web/sites/read

• Microsoft.CostManagement/query/action

• Microsoft.Advisor/advisorScore/read

And it specifically excludes high-risk services like:

• Microsoft.Network/vpnGateways/*

• Microsoft.Network/connections/*

• Microsoft.KeyVault/vaults/*

How to Deploy the Azure Secure Role

Here’s how to lock down your monitoring identity using the custom user role:

1. Create an Azure App Registration (Service Principal):

   Follow Microsoft’s guide to create a service principal and record the Application ID,

Tenant ID, and Client Secret.  

2. Define and Assign the Role:

   Use the JSON file provided (AutoMonX_Azure_MinimalMonitoringReader.json),

AutoMonX_Azure_Minimal Monitoring Reader.json

Download JSON • 4KB

and run the following Powershell commands:  

az role definition create --role-definition @AutoMonx_Azure_MinimalMonitoringReader.json   

az role assignment create --assignee <appId> --role "Minimal Monitoring Reader" --scope /subscriptions/<subscription-id>

3. Configure AutoMonX Sensor Pack for Azure:

Open the AutoMonX Sensor UI, and add the Azure tenant with the credentials from

step 1.  

If you prefer manual configuration, update AutoMonX_AzureSensor.ini or AzureConnProfiles.ini.

4. Enable Encryption (Recommended):

In the AutoMonX UI, tick the encryption checkboxes for App ID, Secret, and Tenant ID. Once encrypted, they are unreadable - even by AutoMonX support. Backup these values securely.

Why This Approach Matters?

Using the minimal monitoring Reader for the Service Principal configured for monitoring, dramatically reduces your risk. If the monitoring identity is ever compromised, it won’t be able to touch your networking infrastructure or secrets. This approach also helps with:

• Meeting internal and external compliance requirements.

• Avoiding over-privileged accounts in audit reports

• Ensuring cleaner RBAC practices across your Azure estate

Need Help?

The AutoMonX team is happy to assist you with implementing secure monitoring. Email us at support@automonx.com or download the role template directly.