EC2 instance has public IP

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Metadata

Id: a8b0c58b-cd25-4b53-9ad0-55bca0be0bc1

Cloud Provider: AWS

Platform: Ansible

Severity: Medium

Category: Networking and Firewall

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Description

EC2 instances and launch templates that automatically receive a public IPv4 address are exposed directly to the internet, increasing the attack surface and the risk of unauthorized access or exploitation.

For Ansible tasks, check the following module properties:

  • For amazon.aws.ec2_launch_template / ec2_launch_template: network_interfaces.associate_public_ip_address
  • For amazon.aws.ec2_instance / ec2_instance: network.assign_public_ip

Each property must be explicitly set to false (or 'no') or omitted. The rule flags resources where the property is truthy (for example, true, yes) because there is no safe default.

Secure examples:

- name: Launch instance without public IP (ec2_instance)
  amazon.aws.ec2_instance:
    name: my-instance
    network:
      assign_public_ip: false

- name: Create launch template without public IP
  amazon.aws.ec2_launch_template:
    name: my-template
    network_interfaces:
      - device_index: 0
        associate_public_ip_address: false

Compliant Code Examples

- name: Launch instance without public IP
  amazon.aws.ec2_instance:
    name: my-instance
    key_name: mykey
    instance_type: t2.micro
    vpc_subnet_id: subnet-29e63245
    network:
      assign_public_ip: false
- name: Create an ec2 launch template
  amazon.aws.ec2_launch_template:
    name: my_template
    image_id: ami-04b762b4289fba92b
    key_name: my_ssh_key
    instance_type: t2.micro
- name: Create an ec2 launch template
  amazon.aws.ec2_launch_template:
    name: "my_template"
    image_id: "ami-04b762b4289fba92b"
    key_name: my_ssh_key
    instance_type: t2.micro
    network_interfaces:
      - interface_type: interface
        ipv6_addresses: []
        mac_address: '0 e: 0 e: 36: 60: 67: cf'
        network_interface_id: eni - 061 dee20eba3b445a
        owner_id: '721066863947'
        source_dest_check: true
        status: " in -use"

Non-Compliant Code Examples

- name: example
  amazon.aws.ec2_instance:
    name: my-instance
    key_name: mykey
    instance_type: t2.micro
    vpc_subnet_id: subnet-29e63245
    network:
      assign_public_ip: yes
- name: Create an ec2 launch template
  amazon.aws.ec2_launch_template:
    name: "my_template"
    image_id: "ami-04b762b4289fba92b"
    key_name: my_ssh_key
    instance_type: t2.micro
    network_interfaces:
      associate_public_ip_address: true
- name: start an instance with a public IP address
  amazon.aws.ec2_instance:
    name: "public-compute-instance"
    key_name: "prod-ssh-key"
    vpc_subnet_id: subnet-5ca1ab1e
    instance_type: c5.large
    security_group: default
    network:
      assign_public_ip: true