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Configure Azure Storage firewall#

Security · Storage Account · 2021_09

Storage Accounts should only accept explicitly allowed traffic.

Description#

By default, storage accounts accept connections from clients on any network. To limit access to selected networks, you must first change the default action.

After changing the default action from Allow to Deny, configure one or more rules to allow traffic. Traffic can be allowed from:

  • Azure services on the trusted service list.
  • IP address or CIDR range.
  • Private endpoint connections.
  • Azure virtual network subnets with a Service Endpoint.

Recommendation#

Consider configuring storage firewall to restrict network access to permitted clients only. Also consider enforcing this setting using Azure Policy.

Examples#

Configure with Azure template#

To deploy Storage Accounts that pass this rule:

  • Set the properties.networkAcls.defaultAction property to Deny.

For example:

Azure Template snippet
{
    "type": "Microsoft.Storage/storageAccounts",
    "apiVersion": "2021-04-01",
    "name": "st0000001",
    "location": "[parameters('location')]",
    "sku": {
        "name": "Standard_GRS"
    },
    "kind": "StorageV2",
    "properties": {
        "supportsHttpsTrafficOnly": true,
        "accessTier": "Hot",
        "allowBlobPublicAccess": false,
        "minimumTlsVersion": "TLS1_2",
        "networkAcls": {
            "defaultAction": "Deny"
        }
    }
}

Configure with Bicep#

To deploy Storage Accounts that pass this rule:

  • Set the properties.networkAcls.defaultAction property to Deny.

For example:

Azure Bicep snippet
resource st0000001 'Microsoft.Storage/storageAccounts@2021-04-01' = {
  name: 'st0000001'
  location: location
  sku: {
    name: 'Standard_GRS'
  }
  kind: 'StorageV2'
  properties: {
    supportsHttpsTrafficOnly: true
    accessTier: 'Hot'
    allowBlobPublicAccess: false
    minimumTlsVersion: 'TLS1_2'
    networkAcls: {
      defaultAction: 'Deny'
    }
  }
}

Notes#

Cloud Shell storage with the tag ms-resource-usage = 'azure-cloud-shell' is excluded. Azure storage firewall is not supported for Cloud Shell storage accounts.

Last update: 2022-12-03

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