Route Table should have a default route for internet traffic control

High Azure General routetables-route-table-default-route

Applies to

Microsoft.Network/routeTables

What CGPulse checks

A resource passes this rule when hasDefaultRoute must equal true. Anything else is reported as a finding with the evaluated property value attached as evidence.

How to fix it

Add a default route (0.0.0.0/0) to control internet-bound traffic through a firewall or NVA. In Azure Portal: Route Table > Routes > Add route. See: https://learn.microsoft.com/en-us/azure/virtual-network/manage-route-table

CLI

az network route-table route create -g "{rg}" --route-table-name "{name}" -n "default-to-nva" --address-prefix 0.0.0.0/0 --next-hop-type VirtualAppliance --next-hop-ip-address "<firewall-ip>"

Bicep

resource routeTable 'Microsoft.Network/routeTables@2024-01-01' = {
  name: '{name}'
  location: location
  properties: {
    routes: [{
      name: 'default-to-nva'
      properties: {
        addressPrefix: '0.0.0.0/0'
        nextHopType: 'VirtualAppliance'
        nextHopIpAddress: '<firewall-private-ip>'
      }
    }]
  }
}

Terraform

resource "azurerm_route_table" "{name}" {
  name                = "{name}"
  resource_group_name = "{rg}"
  location            = var.location
  route {
    name                   = "default-to-nva"
    address_prefix         = "0.0.0.0/0"
    next_hop_type          = "VirtualAppliance"
    next_hop_in_ip_address = "<firewall-private-ip>"
  }
}

Compliance frameworks

Cloud Security: Azure Foundations

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