Cis Azure Compute 2.1.13

Ensure managed identities are configured

Description

Managed identities from Microsoft Entra ID allow App Service apps to securely access other Azure services without the need to provision or rotate any secrets.

Rationale

Using managed identities with App Service apps eliminates the need to store and manage credentials to access Azure resources.

Impact

Minor administrative overhead to configure and manage role assignments for managed identities.

Audit Procedure

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Settings, click Identity.
4. Ensure that in the System assigned pane, the Status is set to On, and an Object (principal) ID is displayed, or that in the User assigned pane, a managed identity is listed.
5. Repeat steps 1-4 for each app.

Using Azure CLI

Run the following command to list web apps:

az webapp list

For each web app, run the following command:

az webapp identity show --resource-group <resource-group-name> --name <app-name> --query type

Ensure the command returns SystemAssigned, UserAssigned, or both.

Using Azure PowerShell

Run the following command to list web apps:

Get-AzWebApp

Run the following command to get the web app in a resource group with a given name:

Get-AzWebapp -ResourceGroupName <resource-group-name> -Name <app-name>

Run the following command to get the assigned identity type for a web app:

$webapp.Identity.Type

Ensure the command returns SystemAssigned, UserAssigned, or both.

Expected Result

The identity type should return SystemAssigned, UserAssigned, or both.

Remediation

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Settings, click Identity.
4. To add a system assigned managed identity:
   1. In the System assigned pane, under Status, click On.
   2. Click Save.
   3. Click Yes.
5. To add a user assigned managed identity:
   1. In the User assigned pane, click Add.
   2. Use the filter box to search for a managed identity.
   3. Select the identity.
   4. Click Add.
6. Repeat steps 1-5 for each app requiring remediation.

Using Azure CLI

For each web app requiring remediation, run the following command to assign a managed identity:

az webapp identity assign --resource-group <resource-group-name> --name <app-name>

Using Azure PowerShell

For each web app requiring remediation, run the following command to assign a managed identity:

Set-AzWebApp -AssignIdentity $True -ResourceGroupName <resource-group-name> -Name <app-name>

Default Value

Managed identities are disabled by default for App Service apps.

References

1. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-identity-management#im-1-use-centralized-identity-and-authentication-system
2. https://learn.microsoft.com/en-us/azure/app-service/overview-managed-identity
3. https://learn.microsoft.com/en-us/cli/azure/webapp
4. https://learn.microsoft.com/en-us/powershell/module/az.websites/get-azwebapp
5. https://learn.microsoft.com/en-us/powershell/module/az.websites/set-azwebapp

Profile

Level 1 | Automated