Microsoft AzureOverview
Storage accounts with the activity log exports can be configured to use Customer Managed Keys (CMK).
Rationale
Configuring the storage account with the activity log export container to use CMKs provides additional confidentiality controls on log data. A given user must have read permission on the corresponding storage account and must be granted decryption permission by the CMK.
Impact
NOTE: You must have your key vault setup to utilize this.
All Audit Logs will be encrypted with a key you provide. You will need to set up customer-managed keys separately, and you will select which key to use via the instructions here. You will be responsible for the keys' lifecycle and will need to manually replace them at your own determined intervals to keep the data secure.
Default Value
By default, storage accounts are encrypted with keys managed by Microsoft.
Remediation guidance
Remediate from Azure Portal
- Go to
Monitor. - Select
Activity log. - Select
Export Activity Logs. - Select a
Subscription. - Note the name of the
Storage Accountfor the diagnostic setting. - Navigate to
Storage accounts. - Click on the storage account.
- Under
Security + networking, clickEncryption. - Next to
Encryption type, selectCustomer-managed keys. - Complete the steps to configure a customer-managed key for encryption of the storage account.
Remediate from Azure CLI
az storage account update --name <name of the storage account> --resource-group <resource group for a storage account> --encryption-key-source=Microsoft.Keyvault --encryption-key-vault --encryption-key-name --encryption-key-version
Remediate from PowerShell
Set-AzStorageAccount -ResourceGroupName <resourceGroupName> -Name <storageAccountName> -KeyvaultEncryption -KeyVaultUri -KeyName
Service-wide remediation
Recommended when many resources are affected: fix the platform baseline first so new resources inherit the secure setting, then remediate the existing flagged resources in batches.
Azure
Use management group or subscription Azure Policy assignments, remediation tasks where supported, landing-zone standards, and IaC modules so drift is prevented at scale.
Operational rollout
- Fix the baseline first at the account, subscription, project, cluster, or tenant scope that owns this control.
- Remediate the currently affected resources in batches, starting with internet-exposed and production assets.
- Re-scan and track approved exceptions with an owner and expiry date.
Query logic
These are the stored checks tied to this control.
Azure Subscription Diagnostic Settings Without CMK
Connectors
Covered asset types
Expected check: eq []
{
storageAccounts(
where: {
NOT: { destinationForSubscriptionDiagnosticSettings_SOME: null }
byokEncrypted: false
}
) {
...AssetFragment
}
}
