The default action on Storage account network rules should be set to deny

Explanation

The default_action for network rules should come into effect when no other rules are matched.

The default action should be set to Deny.

Possible Impact

Network rules that allow could cause data to be exposed publicly

Suggested Resolution

Set network rules to deny

Insecure Example

The following example will fail the azure-storage-default-action-deny check.

resource "azurerm_storage_account_network_rules" "bad_example" {
  
  default_action             = "Allow"
  ip_rules                   = ["127.0.0.1"]
  virtual_network_subnet_ids = [azurerm_subnet.test.id]
  bypass                     = ["Metrics"]
}

Secure Example

The following example will pass the azure-storage-default-action-deny check.

resource "azurerm_storage_account_network_rules" "good_example" {
  
  default_action             = "Deny"
  ip_rules                   = ["127.0.0.1"]
  virtual_network_subnet_ids = [azurerm_subnet.test.id]
  bypass                     = ["Metrics"]
}

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