Cis Azure Storage 5.2.4

5.2.4 Ensure 'Use infrastructure encryption for this vault' is enabled on Recovery Services vaults (Automated)

Description

In addition to using customer-managed keys for encryption at rest in the Recovery Services vault, you can enable an additional layer of platform-managed infrastructure encryption. This dual-layer approach enhances the protection of your backup data.

Rationale

Enabling infrastructure encryption on an Azure Recovery Services vault adds a second layer of protection to backup data, enhancing security and ensuring compliance for sensitive data storage. This dual-layer strategy reduces the risk of unauthorized access by keeping data encrypted even if one layer is compromised.

Impact

Enabling infrastructure encryption on an Azure Recovery Services vault does not incur additional costs; however infrastructure encryption must be set when configuring the encryption of the vault for the first time and requires customer-managed keys for encryption at rest. Once configured, the infrastructure encryption setting cannot be changed. This recommendation is linked to Ensure that backup data in Recovery Services vaults is encrypted using customer-managed keys (CMK) and should be applied alongside it if you choose to implement this recommendation.

Audit Procedure

Audit from Azure Portal

1. Go to Recovery Services vaults.
2. Click the name of a Recovery Services vault.
3. Under Settings, click Properties.
4. Under Encryption Settings, click Update.
5. Under Infrastructure encryption, ensure the box next to Use infrastructure encryption for this vault is checked.
6. Repeat steps 1-5 for each Recovery Services vault.

Audit from Azure CLI

Run the following command to list Recovery Services vaults:

az backup vault list

For each Recovery Services vault, run the following command:

az backup vault encryption show --resource-group <resource-group> --name <recovery-services-vault>

Ensure that infrastructureEncryptionState is set to Enabled.

Audit from PowerShell

Run the following command to list Recovery Services vaults:

Get-AzRecoveryServicesVault

Run the following command to get the Recovery Services vault in a resource group with a given name:

$vault = Get-AzRecoveryServicesVault -ResourceGroupName <resource-group> -Name <recovery-services-vault>

Run the following command to get the infrastructure encryption setting for the Recovery Services vault:

$vault.Properties.EncryptionProperty.InfrastructureEncryption

Ensure that the command returns Enabled. Repeat for each Recovery Services vault.

Expected Result

• infrastructureEncryptionState is set to Enabled
• In Azure Portal, Use infrastructure encryption for this vault is checked
• PowerShell returns Enabled for $vault.Properties.EncryptionProperty.InfrastructureEncryption

Remediation

Remediate from Azure Portal

After configuring a customer-managed key for encryption, next to Infrastructure Encryption, click the radio button next to Enabled.

Remediate from Azure CLI

For each Recovery Services vault requiring remediation, run the following command to assign a customer-managed encryption key and enable infrastructure encryption:

az backup vault encryption update --resource-group <resource-group> --name <recovery-services-vault> --encryption-key-id <cmk-uri> --mi-system-assigned --infrastructure-encryption Enabled

Note: Use --mi-user-assigned with the above command to provide a UserAssigned Identity Id.

Remediate from PowerShell

For each Recovery Services vault requiring remediation, run the following command to assign a customer-managed encryption key and enable infrastructure encryption:

Set-AzRecoveryServicesVaultProperty -VaultId <recovery-services-vault-id> -EncryptionKeyId <cmk-uri> -UseSystemAssignedIdentity $true -InfrastructureEncryption

Note: Use -UseSystemAssignedIdentity $false with the above command and -UserAssignedIdentity to provide a UserAssigned Identity Id.

Default Value

Infrastructure encryption is disabled by default on Azure Recovery Services vaults.

References

1. https://learn.microsoft.com/en-us/azure/backup/backup-encryption
2. https://learn.microsoft.com/en-us/cli/azure/backup/vault/encryption
3. https://learn.microsoft.com/en-us/powershell/module/az.recoveryservices/get-azrecoveryservicesvault
4. https://learn.microsoft.com/en-us/powershell/module/az.recoveryservices/set-azrecoveryservicesvaultproperty

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Level 2 | Automated