Cis Azure Foundations 6.2

Ensure that Resource Locks are set for Mission-Critical Azure Resources

Description

Resource Manager Locks provide a way for administrators to lock down Azure resources to prevent deletion of, or modifications to, a resource. These locks sit outside of the Role Based Access Controls (RBAC) hierarchy and, when applied, will place restrictions on the resource for all users. These locks are very useful when there is an important resource in a subscription that users should not be able to delete or change. Locks can help prevent accidental and malicious changes or deletion.

While an automated assessment procedure exists for this recommendation, the assessment status remains manual. Determining resources that require resource locks depends on the context and requirements of each organization and environment.

Rationale

As an administrator, it may be necessary to lock a subscription, resource group, or resource to prevent other users in the organization from accidentally deleting or modifying critical resources. The lock level can be set to CanNotDelete or ReadOnly to achieve this purpose.

• CanNotDelete means authorized users can still read and modify a resource, but they cannot delete the resource.
• ReadOnly means authorized users can read a resource, but they cannot delete or update the resource. Applying this lock is similar to restricting all authorized users to the permissions granted by the Reader role.

Impact

There can be unintended outcomes of locking a resource. Applying a lock to a parent service will cause it to be inherited by all resources within. Conversely, applying a lock to a resource may not apply to connected storage, leaving it unlocked. Please see the documentation for further information.

Audit Procedure

Using Azure Portal

1. Navigate to the specific Azure Resource or Resource Group.
2. Click on Locks.
3. Ensure the lock is defined with name and description, with type Read-only or Delete as appropriate.

Using Azure CLI

Review the list of all locks set currently:

az lock list --resource-group <resourcegroupname> --resource-name <resourcename> --namespace <Namespace> --resource-type <type> --parent ""

Using PowerShell

Run the following command to list all resources:

Get-AzResource

For each resource, run the following command to check for Resource Locks:

Get-AzResourceLock -ResourceName <Resource Name> -ResourceType <Resource Type> -ResourceGroupName <Resource Group Name>

Review the output of the Properties setting. Compliant settings will have the CanNotDelete or ReadOnly value.

Expected Result

Mission-critical Azure resources should have appropriate resource locks (CanNotDelete or ReadOnly) applied to prevent accidental or malicious modification or deletion.

Remediation

Remediate from Azure Portal

1. Navigate to the specific Azure Resource or Resource Group.
2. For each mission critical resource, click on Locks.
3. Click Add.
4. Give the lock a name and a description, then select the type, Read-only or Delete as appropriate.
5. Click OK.

Remediate from Azure CLI

To lock a resource, provide the name of the resource, its resource type, and its resource group name.

az lock create --name <LockName> --lock-type <CanNotDelete/Read-only> --resource-group <resourceGroupName> --resource-name <resourceName> --resource-type <resourceType>

Remediate from PowerShell

Get-AzResourceLock -ResourceName <Resource Name> -ResourceType <Resource Type> -ResourceGroupName <Resource Group Name> -Locktype <CanNotDelete/Read-only>

Default Value

By default, no locks are set.

References

1. https://learn.microsoft.com/en-us/azure/azure-resource-manager/management/lock-resources
2. https://learn.microsoft.com/en-us/azure/cloud-adoption-framework/ready/landing-zone/design-area/management-platform#inventory-and-visibility-recommendations
3. https://learn.microsoft.com/en-us/azure/governance/blueprints/concepts/resource-locking
4. https://learn.microsoft.com/en-us/security/benchmark/azure/mcsb-asset-management#am-4-limit-access-to-asset-management

CIS Controls

Profile

Level 2 | Manual