3.7 Ensure that 'Public Network Access' is 'Disabled' for storage accounts

Information

Disallowing public network access for a storage account overrides the public access settings for individual containers in that storage account for Azure Resource Manager Deployment Model storage accounts. Azure Storage accounts that use the classic deployment model will be retired on August 31, 2024.

Rationale:

The default network configuration for a storage account permits a user with appropriate permissions to configure public network access to containers and blobs in a storage account. Keep in mind that public access to a container is always turned off by default and must be explicitly configured to permit anonymous requests. It grants read-only access to these resources without sharing the account key, and without requiring a shared access signature. It is recommended not to provide public network access to storage accounts until, and unless, it is strongly desired. A shared access signature token or Azure AD RBAC should be used for providing controlled and timed access to blob containers.

Impact:

Access will have to be managed using shared access signatures or via Azure AD RBAC.

Solution

From Azure Portal
First, follow Microsoft documentation and create shared access signature tokens for your blob containers. Then,

Go to Storage Accounts

For each storage account, under the Security + networking section, click Networking

Set Public Network Access to Disabled.

From Azure CLI
Set 'Public Network Access' to Disabled on the storage account

az storage account update --name <storage-account> --resource-group <resource-group> --public-network-access Disabled

From PowerShell
For each Storage Account, run the following to set the PublicNetworkAccess setting to Disabled

Set-AzStorageAccount -ResourceGroupName <resource group name> -Name <storage account name> -PublicNetworkAccess Disabled

Default Value:

By default, Public Network Access is set to Enabled from all networks for the Storage Account.

See Also

https://workbench.cisecurity.org/benchmarks/12346

Item Details

Category: ACCESS CONTROL, MEDIA PROTECTION

References: 800-53|AC-3, 800-53|AC-5, 800-53|AC-6, 800-53|MP-2, CSCv7|14.6

Plugin: microsoft_azure

Control ID: 04d4a33d673be3d0bfc7a4206a8fa64cc8505075f5c0b710fbfa73c4a7137653