Cis Azure Foundations 5.27

Ensure there are between 2 and 3 subscription owners

Description

The Owner role in Azure grants full control over all resources in a subscription, including the ability to assign roles to others.

Rationale

Limit the number of security principals (users, groups, service principals, and managed identities) assigned the Owner role to between 2 and 3. If groups are used, ensure their membership is tightly controlled and regularly reviewed to avoid privilege sprawl.

Impact

Implementation may require changes in administrative workflows or the redistribution of roles and responsibilities. The recommendation to have between 2 and 3 Owners per subscription must account for all security principals that can be assigned the Owner role, not just individual users. This includes:

• User accounts
• Entra ID groups
• Service principals (used by applications or automation)
• Managed identities (system-assigned or user-assigned)

Audit Procedure

Using Azure Portal

1. Go to Subscriptions.
2. Click the name of a subscription.
3. Click Access Controls (IAM).
4. Click Role assignments.
5. Click Role : All.
6. Click the arrow next to All.
7. Click Owner.
8. Ensure a minimum of 2 and a maximum of 3 members are returned.
9. Repeat steps 1-8 for each subscription.

Using Azure CLI

az role assignment list --role Owner --scope /subscriptions/<subscription-id> \
  --query "[].{PrincipalName:principalName, Type:principalType}"

Ensure a minimum of 2 and a maximum of 3 members are returned. For each Owner assignment, check: If principalType == Group, review group membership. If principalType == ServicePrincipal or ManagedIdentity, validate necessity and scope. Repeat for each subscription.

Using PowerShell

Get-AzRoleAssignment -RoleDefinitionName Owner -Scope /subscriptions/<subscription-id>

Ensure a minimum of 2 and a maximum of 3 members are returned. Repeat for each subscription.

Using Azure Policy

• Policy ID: 09024ccc-0c5f-475e-9457-b7c0d9ed487b - Name: 'There should be more than one owner assigned to your subscription'
• Policy ID: 4f11b553-d42e-4e3a-89be-32ca364cad4c - Name: 'A maximum of 3 owners should be designated for your subscription'

Expected Result

Each subscription should have a minimum of 2 and a maximum of 3 owners assigned.

Remediation

Using Azure Portal

1. Go to Subscriptions.
2. Click the name of a subscription.
3. Click Access Controls (IAM).
4. Click Role assignments.
5. Click Role : All.
6. Click the arrow next to All.
7. Click Owner.
8. Check the box next to members from whom the owner role should be removed.
9. Click Delete.
10. Click Yes.
11. Repeat steps 1-10 for each subscription requiring remediation.

Using Azure CLI

az role assignment delete --ids <role-assignment-ids>

Default Value

A subscription has 1 owner by default.

References

1. https://learn.microsoft.com/en-us/cli/azure/role/assignment
2. https://learn.microsoft.com/en-us/powershell/module/az.resources/get-azroleassignment
3. https://learn.microsoft.com/en-us/azure/role-based-access-control/built-in-roles/privileged#owner
4. https://learn.microsoft.com/en-us/azure/role-based-access-control/role-assignments-portal-subscription-admin

CIS Controls

Profile

Level 1 | Automated