Enforce GCP Storage Buckets Are Not Publicly Accessible
Cloud Storage buckets, like other GCP resources, have Cloud Identity and Access Management (IAM) policies configured to determine who can have access to the storage resources. To deny access from anonymous and public users, remove the bindings for "allUsers" and "allAuthenticatedUsers" members from the storage bucket's IAM policy. The "allUsers" is a special member identifier that represents any user on the Internet, including authenticated and unauthenticated users, while the "allAuthenticatedUsers" is an identifier that represents any user or service account that can sign in to Google Cloud Platform (GCP) with a Google account.
This policy pack can help you configure the following settings for storage buckets:
- Remove access for non-trusted members
- Do not allow
allUsers
access to buckets - Do not allow
allAuthenticatedUsers
access to buckets
Getting Started
Requirements
- Terraform
- Guardrails mods:
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.comexport TURBOT_ACCESS_KEY=acce6ac5-access-key-hereexport TURBOT_SECRET_KEY=a8af61ec-secret-key-here
Please see Turbot Guardrails Provider authentication for additional authentication methods.
Usage
Install Policy Pack
NoteBy 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.gitcd guardrails-samples/policy_packs/gcp/storage/enforce_buckets_are_not_publicly_accessible
Run the Terraform to create the policy pack in your workspace:
terraform initterraform 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
TipYou 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" "gcp_storage_bucket_policy_trusted_access" { resource = turbot_policy_pack.main.id type = "tmod:@turbot/gcp-storage#/policy/types/bucketPolicyTrustedAccess" # value = "Check: Trusted Access > *" value = "Enforce: Trusted Access > *"}
Then re-apply the changes:
terraform planterraform apply