Control: 4.11 Ensure Storage for Critical Data are Encrypted with Customer Managed Keys

Description

Enable sensitive data encryption at rest using Customer Managed Keys (CMK) rather than Microsoft Managed keys.

By default, data in the storage account is encrypted using Microsoft Managed Keys at rest. All Azure Storage resources are encrypted, including blobs, disks, files, queues, and tables. All object metadata is also encrypted. If you want to control and manage this encryption key yourself, however, you can specify a customer-managed key. That key is used to protect and control access to the key that encrypts your data. You can also choose to automatically update the key version used for Azure Storage encryption whenever a new version is available in the associated Key Vault.

While it is possible to automate the assessment of this recommendation, the assessment status for this recommendation remains 'Manual.' This is because the recommendation pertains to storage accounts that store critical data and is therefore not applicable to all storage accounts.

Remediation

From Azure Portal

1. Go to Storage Accounts.
2. For each storage account, under Security + networking, go to Encryption.
3. Set Encryption type to Customer-managed keys.
4. Select an encryption key or enter a key URI.
5. Click Save.

Default Value

By default, Encryption type is set to Microsoft Managed Keys.