The default network access rule for Storage Accounts should be set to deny

Warning: This rule will be deprecated 18 December 2023 as part of the update to Azure CIS version 2.0.0


Restricting default network access provides a layer of security, because storage accounts accept connections from clients on any network. To limit access to selected networks, change the default action.


Configure storage accounts to deny access to traffic from all networks (including internet traffic). Grant access to traffic from specific Azure Virtual networks, allowing a secure network boundary for specific applications to be built. Access can also be granted to public internet IP address ranges, to enable connections from specific internet or on-premises clients. When network rules are configured, only applications from allowed networks can access a storage account. When calling from an allowed network, applications continue to require proper authorization (a valid access key or SAS token) to access the storage account.


All allowed networks will need to be whitelisted on each specific network, creating administrative overhead. This may result in loss of network connectivity, so do not turn on for critical resources during business hours.


From the console

  1. Go to Storage Accounts.
  2. For each storage account, click on the Networking blade.
  3. Click the Firewalls and virtual networks heading.
  4. Ensure that you have elected to allow access from Selected networks.
  5. Add rules to allow traffic from specific networks and click Save to apply your changes.

From the command line

Use the following command to update the default action to deny:

az storage account update --name <StorageAccountName> --resource-group <resourceGroupName> --default-action Deny