azure-nic-ip-forwarding-check: Review Network Interfaces with IP Forwarding Enabled

id: azure-nic-ip-forwarding-check
info:
  name: Review Network Interfaces with IP Forwarding Enabled
  author: princechaddha
  severity: medium
  description: |
    Ensure that all Microsoft Azure network interfaces (NICs) with IP forwarding enabled are regularly reviewed for security and compliance reasons. IP forwarding allows a virtual machine (VM) to receive and send network traffic not intended for its own IP, used primarily by network virtual appliances.
  impact: |
    If improperly managed, IP forwarding can expose Azure environments to security risks, potentially allowing traffic redirection or eavesdropping.
  remediation: |
    Regularly review and validate the necessity of IP forwarding settings on Azure NICs. Ensure that only authorized and secure virtual appliances use this feature.
  reference:
    - https://docs.microsoft.com/en-us/azure/virtual-network/ip-forwarding
  tags: cloud,devops,azure,microsoft,nic,azure-cloud-config

flow: |
  code(1);
  for (let NicData of iterate(template.nicdata)) {
    NicData = JSON.parse(NicData)
    set("name", NicData.name)
    set("resourcegroup", NicData.resourceGroup)
    code(2)
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      az network nic list --output json --query '[*].{name:name, resourceGroup:resourceGroup}'

    extractors:
      - type: json
        name: nicdata
        internal: true
        json:
          - '.[]'

  - engine:
      - sh
      - bash
    source: |
      az network nic show --name $name --resource-group $resourcegroup --query 'enableIpForwarding'

    matchers:
      - type: word
        words:
          - "true"

    extractors:
      - type: dsl
        dsl:
          - 'nsg + " has IP forwarding enabled"'
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