Cis Azure Storage 5.1.6

5.1.6 Ensure 'Cross Subscription Restore' is set to 'Disabled' or 'Permanently Disabled' on Backup vaults (Automated)

Description

Disable cross subscription restore for Backup vaults to ensure that backup data can only be restored within the same subscription as the Backup vault, preventing restoration to targets in other subscriptions.

Rationale

Cross subscription restores increases security risks by widening access to sensitive backup data, potentially leading to accidental or intentional exposure, unauthorized access, or data exfiltration across environments.

Impact

Organizations may need to consider alternatives for disaster recovery scenarios, and if utilizing multiple subscriptions, may need to make adjustments or consider alternatives for data access. Costs could be incurred if alternative or additional backup infrastructure is required to account for the disabling of cross subscription restore.

Audit Procedure

Audit from Azure Portal

1. Go to Backup vaults.
2. Click the name of a Backup vault.
3. Under Manage, click Properties.
4. Under Vault Settings, ensure that Cross Subscription Restore is set to Disabled or Permanently Disabled.
5. Repeat steps 1-4 for each Backup vault.

Audit from Azure CLI

Run the following command to list Backup vaults:

az dataprotection backup-vault list

For each Backup vault, run the following command:

az dataprotection backup-vault show --resource-group <resource-group> --vault-name <backup-vault>

Ensure that under properties > featureSettings > crossSubscriptionRestoreSettings, state is set to Disabled or PermanentlyDisabled.

Audit from PowerShell

Run the following command to list Backup vaults:

Get-AzDataProtectionBackupVault

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

$vault = Get-AzDataProtectionBackupVault -ResourceGroupName <resource-group> -VaultName <backup-vault>

Run the following command to get the cross subscription restore setting for the Backup vault:

$vault.CrossSubscriptionRestoreState

Ensure that the command returns Disabled or PermanentlyDisabled. Repeat for each Backup vault.

Audit from Azure Policy

If referencing a digital copy of this Benchmark, clicking a Policy ID will open a link to the associated Policy definition in Azure. If referencing a printed copy, you can search Policy IDs from this URL: https://portal.azure.com/#view/Microsoft_Azure_Policy/PolicyMenuBlade/~/Definitions

• Policy ID: 4d479a11-f2b5-4f0a-bb1e-d2332aa95cda
• Name: '[Preview]: Disable Cross Subscription Restore for Backup Vaults'

Expected Result

Cross Subscription Restore should be Disabled or Permanently Disabled in the Azure Portal, or properties.featureSettings.crossSubscriptionRestoreSettings.state should be Disabled or PermanentlyDisabled in CLI output, or $vault.CrossSubscriptionRestoreState should return Disabled or PermanentlyDisabled in PowerShell.

Remediation

Remediate from Azure Portal

1. Go to Backup vaults.
2. Click the name of a Backup vault.
3. Under Manage, click Properties.
4. Under Vault Settings, next to Cross Subscription Restore, click Update.
5. Select the radio button next to Disable Cross Subscription Restore or Permanently disable Cross Subscription Restore on this vault.
6. If selecting to permanently disable cross subscription restore, check the box next to Are you sure you want to permanently disable Cross Subscription Restore? Once disabled, it cannot be re-enabled.
7. Click Update.
8. Repeat steps 1-7 for each Backup vault requiring remediation.

Remediate from Azure CLI

For each Backup vault requiring remediation, run the following command to disable cross subscription restore:

az dataprotection backup-vault update --resource-group <resource-group> --vault-name <backup-vault> --cross-subscription-restore-state Disabled

Note: Use --cross-subscription-restore-state PermanentlyDisabled with the above command to permanently disable cross subscription restore.

Remediate from PowerShell

For each Backup vault requiring remediation, run the following command to disable cross subscription restore:

Update-AzDataProtectionBackupVault -ResourceGroupName <resource-group> -VaultName <backup-vault> -CrossSubscriptionRestoreState Disabled

Note: Use -CrossSubscriptionRestoreState PermanentlyDisabled with the above command to permanently disable cross subscription restore.

Default Value

Cross subscription restore is enabled by default on Backup vaults.

References

1. https://learn.microsoft.com/en-us/cli/azure/dataprotection/backup-vault
2. https://learn.microsoft.com/en-us/powershell/module/az.dataprotection/get-azdataprotectionbackupvault
3. https://learn.microsoft.com/en-us/powershell/module/az.dataprotection/update-azdataprotectionbackupvault
4. https://learn.microsoft.com/en-us/azure/backup/create-manage-backup-vault#cross-subscription-restore-using-azure-portal

Additional Information

If cross subscription restore is permanently disabled on a vault, it cannot be re-enabled.

CIS Controls

Profile

Level 1 | Automated