Enforce Trusted Access for Policies on AWS S3 Buckets

Ensuring that S3 bucket policies do not allow access to all AWS users or non-trusted AWS accounts is crucial for enhancing security. This measure helps protect sensitive data by restricting bucket access to trusted accounts only, thereby reducing the risk of unauthorized access and ensuring compliance with security best practices and regulatory requirements.

This policy pack can help you configure the following settings for S3 buckets:

Set trusted accounts
Set trusted services
Set trusted identity providers
Set trusted organizations
Set trusted organization path restrictions
Set trusted CloudFront origin access identities
Revoke untrusted access from buckets

Documentation

Review Policy settings →

Getting Started

Requirements

Terraform
Guardrails mods:
- @turbot/aws-s3

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/s3/enforce_trusted_access_for_policies_on_buckets

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_s3_bucket_policy_trusted_access" {
  resource = turbot_policy_pack.main.id
  type     = "tmod:@turbot/aws-s3#/policy/types/bucketPolicyTrustedAccess"
  # value    = "Check: Trusted Access"
  value    = "Enforce: Revoke untrusted access"
}

Then re-apply the changes:

terraform plan
terraform apply