ExpressRoute virtual network gateway does not use an availability zone SKU Affecting Network service in Azure

Snyk CCSS

Network/ Redundancy

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Frameworks

CIS-ControlsCSA-CCM

Snyk IDSNYK-CC-00461
creditSnyk Research Team

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Description

Consider deploying ExpressRoute gateways with an availability zone SKU to improve reliability of virtual network gateways.

How to fix?

When properties.gatewayType is set to ExpressRoute, set properties.sku.tier to ErGw1AZ, ErGw2AZ, or ErGw3AZ.

Example Configuration

{
  "$schema": "https://schema.management.azure.com/schemas/2019-04-01/deploymentTemplate.json#",
  "contentVersion": "1.0.0.0",
  "parameters": {},
  "resources": [
    {
      "type": "Microsoft.Network/virtualNetworkGateways",
      "apiVersion": "2021-03-01",
      "name": "arm-461-allowed2",
      "location": "West Europe",
      "properties": {
        "gatewayType": "ExpressRoute",
        "sku": {
          "name": "ErGw3AZ",
          "tier": "ErGw3AZ"
        }
      }
    }
  ]
}

When type is set to ExpressRoute, set sku to ErGw1AZ, ErGw2AZ, or ErGw3AZ.

Example Configuration

resource "azurerm_virtual_network_gateway" "allowed" {
  name                = "test-virt-net-gw"
  location            = azurerm_resource_group.example.location
  resource_group_name = azurerm_resource_group.example.name

  type     = "ExpressRoute"
  vpn_type = "RouteBased"

  active_active = false
  enable_bgp    = false
  sku           = "ErGw3AZ"
  generation    = "None"

  ip_configuration {
    name                          = "vnetGatewayConfig"
    public_ip_address_id          = azurerm_public_ip.example.id
    private_ip_address_allocation = "Dynamic"
    subnet_id                     = azurerm_subnet.example.id
  }
}