nuclei-templates/cloud/aws/vpc/vpn-tunnel-down.yaml

id: vpn-tunnel-down
info:
  name: AWS VPN Tunnel Down
  author: princechaddha
  severity: high
  description: |
    Ensures AWS VPN tunnels are in an UP state, facilitating uninterrupted network traffic through the Virtual Private Network.
  impact: |
    If a VPN tunnel is DOWN, it could disrupt network connectivity and access to resources in your VPC, impacting business operations.
  remediation: |
    Monitor VPN tunnel status via the AWS Management Console or CLI. If a tunnel is DOWN, troubleshoot according to AWS documentation and ensure redundancy by configuring multiple tunnels.
  reference:
    - https://docs.aws.amazon.com/vpn/latest/s2svpn/VPNConnections.html
  metadata:
    max-request: 2
  tags: cloud,devops,aws,amazon,vpn,aws-cloud-config
variables:
  region: "us-east-1"

flow: |
  code(1)
  for(let VpnConnectionIds of iterate(template.vpnconnactions)){
    set("vpnid", VpnConnectionIds)
    code(2)
  }

self-contained: true
code:
  - engine:
      - sh
      - bash
    source: |
      aws ec2 describe-vpn-connections --region $region --filters "Name=state,Values=available" --query 'VpnConnections[*].VpnConnectionId' --output json

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

  - engine:
      - sh
      - bash
    source: |
         aws ec2 describe-vpn-connections --region $region --vpn-connection-ids $vpnid --query 'VpnConnections[*].VgwTelemetry[*].Status[]'

    matchers:
      - type: word
        words:
          - "DOWN"

    extractors:
      - type: dsl
        dsl:
          - 'vpnid + " VPN tunnel is down"'
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