Enforce AWS EC2 Instances Do Not Have Internet Access via Subnets

Enforcing that AWS EC2 instances do not have internet access via subnets is critical for maintaining a secure and controlled network environment. This measure ensures that instances are isolated from the internet, reducing the risk of unauthorized access and potential data breaches, and enhancing security by restricting outbound traffic to approved and monitored channels.

This policy pack can help you configure the following settings for EC2 instances:

• Stop/Terminate instances that have internet access via subnets

Documentation

• Review Policy settings →

Getting Started

Requirements

• Terraform
• Guardrails mods:
  • @turbot/aws-ec2

Credentials

To create a policy pack through Terraform:

• Ensure you have Turbot/Admin permissions (or higher) in Guardrails
• Create access keys in Guardrails

And then set your credentials:

export TURBOT_WORKSPACE=myworkspace.acme.com
export TURBOT_ACCESS_KEY=acce6ac5-access-key-here
export TURBOT_SECRET_KEY=a8af61ec-secret-key-here

Please see Turbot Guardrails Provider authentication for additional authentication methods.

Usage

Install Policy Pack

Note

By default, installed policy packs are not attached to any resources.

Policy packs must be attached to resources in order for their policy settings to take effect.

Clone:

git clone https://github.com/turbot/guardrails-samples.git
cd guardrails-samples/policy_packs/aws/ec2/enforce_instances_do_not_have_internet_access_via_subnets

Run the Terraform to create the policy pack in your workspace:

terraform init
terraform plan

Then apply the changes:

terraform apply

Apply Policy Pack

Log into your Guardrails workspace and attach the policy pack to a resource.

If this policy pack is attached to a Guardrails folder, its policies will be applied to all accounts and resources in that folder. The policy pack can also be attached to multiple resources.

For more information, please see Policy Packs.

Enable Enforcement

Tip

You can also update the policy settings in this policy pack directly in the Guardrails console.

Please note your Terraform state file will then become out of sync and the policy settings should then only be managed in the console.

By default, the policies are set to Check in the pack's policy settings. To enable automated enforcements, you can switch these policies settings by adding a comment to the Check setting and removing the comment from one of the listed enforcement options:

resource "turbot_policy_setting" "aws_ec2_instance_approved" {
  resource = turbot_policy_pack.main.id
  type     = "tmod:@turbot/aws-ec2#/policy/types/instanceApproved"
  # value    = "Check: Approved"
  value    =  "Enforce: Stop unapproved"
  # value    =  "Enforce: Delete unapproved if new"
}

Then re-apply the changes:

terraform plan
terraform apply