Cis Azure Compute 2.2.12

Ensure managed identities are configured

Description

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

Rationale

Using managed identities with App Service deployment slots 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 Deployment, click Deployment slots.
4. Click the name of a deployment slot.
5. Under Settings, click Identity.
6. 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.
7. Repeat steps 1-6 for each app and deployment slot.

Using Azure CLI

Run the following command to list apps:

az webapp list

For each app, run the following command to list deployment slots:

az webapp deployment slot list --resource-group <resource-group-name> --name <app-name>

For each deployment slot, ensure that identity contains type set to SystemAssigned, UserAssigned, or both.

Using Azure PowerShell

Run the following command to list apps:

Get-AzWebApp

Run the following command to list deployment slots for an app:

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

Run the following command to get the deployment slot with a given name:

$slot = Get-AzWebAppSlot -ResourceGroupName <resource-group-name> -Name <app-name> -Slot <deployment-slot-name>

Run the following command to get the identity type setting for the deployment slot:

$slot.identity.Type

Ensure the command returns SystemAssigned, UserAssigned, or both. Repeat for each app and deployment slot.

Expected Result

The identity.Type property should return SystemAssigned, UserAssigned, or SystemAssigned, UserAssigned.

Remediation

Using Azure Portal

1. Go to App Services.
2. Click the name of an app.
3. Under Deployment, click Deployment slots.
4. Click the name of a deployment slot.
5. Under Settings, click Identity.
6. To add a system assigned managed identity:
   1. In the System assigned pane, under Status, click On.
   2. Click Save.
   3. Click Yes.
7. 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.
8. Repeat steps 1-7 for each app and deployment slot requiring remediation.

Using Azure PowerShell

For each deployment slot requiring remediation, run the following command to assign a system-assigned managed identity:

Set-AzWebAppSlot -ResourceGroupName <resource-group-name> -Name <app-name> -Slot <deployment-slot-name> -AssignIdentity $true

Default Value

Managed identities are disabled by default for App Service deployment slots.

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/get-azwebappslot
6. https://learn.microsoft.com/en-us/powershell/module/az.websites/set-azwebappslot

Profile

Level 1 | Automated