| name | cis-azure-storage-17.6 |
| description | Ensure 'Allow Azure services on the trusted services list to access this storage account' is Enabled for Storage Account Access |
| category | cis-azure-storage |
| version | 1.0.0 |
| author | cyberstrike-official |
| tags | ["cis","azure","storage","storage-accounts","networking"] |
| cis_id | 17.6 |
| cis_benchmark | CIS Microsoft Azure Storage Services Benchmark v1.0.0 |
| tech_stack | ["azure"] |
| cwe_ids | [] |
| chains_with | [] |
| prerequisites | [] |
| severity_boost | {} |
17.6 Ensure 'Allow Azure services on the trusted services list to access this storage account' is Enabled for Storage Account Access (Automated)
Description
NOTE: This recommendation assumes that the Public network access parameter is set to Enabled from selected virtual networks and IP addresses. Please ensure the prerequisite recommendation has been implemented before proceeding:
- Ensure Default Network Access Rule for Storage Accounts is Set to Deny
Some Azure services that interact with storage accounts operate from networks that can't be granted access through network rules. To help this type of service work as intended, allow the set of trusted Azure services to bypass the network rules. These services will then use strong authentication to access the storage account. If the Allow Azure services on the trusted services list to access this storage account exception is enabled, the following services are granted access to the storage account: Azure Backup, Azure Data Box, Azure DevTest Labs, Azure Event Grid, Azure Event Hubs, Azure File Sync, Azure HDInsight, Azure Import/Export, Azure Monitor, Azure Networking Services, and Azure Site Recovery (when registered in the subscription).
Rationale
Turning on firewall rules for a storage account will block access to incoming requests for data, including from other Azure services. We can re-enable this functionality by allowing access to trusted Azure services through networking exceptions.
Impact
This creates authentication credentials for services that need access to storage resources so that services will no longer need to communicate via network request. There may be a temporary loss of communication as you set each Storage Account. It is recommended to not do this on mission-critical resources during business hours.
Audit Procedure
Audit from Azure Portal
- Go to
Storage Accounts.
- For each storage account, under
Security + networking, click Networking.
- Click on the
Firewalls and virtual networks heading.
- Under
Exceptions, ensure that Allow Azure services on the trusted services list to access this storage account is checked.
Audit from Azure CLI
Ensure bypass contains AzureServices:
az storage account list --query '[*].networkRuleSet'
Audit from PowerShell
