Alibaba Cloud
AWS
Google CloudOverview
Publicly writable buckets allow anyone to upload, modify, and/or delete data from your buckets. This can lead to data loss, malware spread, and increased costs.
If you indeed want to allow your users to upload objects to your buckets, you can either let your application handle it or you (your application) can generate signed URLs granting the permission for a certain action at a certain path:
AWS
Google Cloud
Alibaba
Remediation guidance
AWS
- https://docs.aws.amazon.com/AmazonS3/latest/userguide/access-control-block-public-access.html
Google Cloud
- https://cloud.google.com/storage/docs/access-control#public_access_prevention
Alibaba Cloud
- https://www.alibabacloud.com/help/en/object-storage-service/latest/access-and-control-overview
Multiple Remediation Paths
AWS
SERVICE-WIDE (RECOMMENDED when many resources are affected): Deploy centralized guardrails and remediation using AWS Config Conformance Packs and (if applicable) AWS Organizations SCPs.
aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml
ASSET-LEVEL: Apply the resource-specific remediation steps above to only the affected assets.
PREVENTIVE: Add CI/CD policy checks (CloudFormation/Terraform validation) before deployment to prevent recurrence.
Google Cloud
SERVICE-WIDE (RECOMMENDED when many resources are affected): Enforce Organization Policies at org/folder level so new resources inherit secure defaults.
gcloud org-policies set-policy policy.yaml
ASSET-LEVEL: Use the product-specific remediation steps above for only the impacted project/resources.
PREVENTIVE: Use org policy constraints/custom constraints and enforce checks in deployment pipelines.
References for Service-Wide Patterns
- AWS Config Conformance Packs: https://docs.aws.amazon.com/config/latest/developerguide/conformance-packs.html
- AWS Organizations SCP examples: https://docs.aws.amazon.com/organizations/latest/userguide/orgs_manage_policies_scps_examples.html
- GCP Organization Policy overview: https://cloud.google.com/resource-manager/docs/organization-policy/overview
- GCP Organization policy constraints catalog: https://cloud.google.com/resource-manager/docs/organization-policy/org-policy-constraints
- gcloud org-policies: https://cloud.google.com/sdk/gcloud/reference/org-policies
Operational Rollout Workflow
Use this sequence to reduce risk and avoid repeated drift.
1. Contain at Service-Wide Scope First (Recommended)
- AWS: deploy/adjust organization conformance packs and policy guardrails.
aws configservice put-organization-conformance-pack --organization-conformance-pack-name <pack-name> --template-s3-uri s3://<bucket>/<template>.yaml
- Google Cloud: apply organization policy constraints at org/folder scope.
gcloud org-policies set-policy policy.yaml
2. Remediate Existing Affected Assets
- Execute the control-specific Console/CLI steps documented above for each flagged resource.
- Prioritize internet-exposed and production assets first.
3. Validate and Prevent Recurrence
- Re-scan after each remediation batch.
- Track exceptions with owner and expiry date.
- Add preventive checks in IaC/CI pipelines.
Query logic
These are the stored checks tied to this control.
Publicly Writable AWS Buckets
Connectors
Covered asset types
Expected check: eq []
{ buckets( where: { cloudProvider: "aws" publicAccessBlocked: false OR: [ { hasBucketACLGrant_SOME: { OR: [ { granteeURI: "http://acs.amazonaws.com/groups/global/AllUsers" } { granteeURI: "http://acs.amazonaws.com/groups/global/AuthenticatedUsers" } ] permission_IN: ["WRITE", "WRITE_ACP", "FULL_CONTROL"] } } { bucketPolicy: { AND: [ { statements_SOME: { effect: "Allow" OR: [ { actions_INCLUDES: "s3:PutObject" } { actions_INCLUDES: "s3:PutObjectAcl" } { actions_INCLUDES: "s3:CreateMultipartUpload" } { actions_INCLUDES: "s3:UploadPart" } { actions_INCLUDES: "s3:DeleteObject" } { actions_INCLUDES: "s3:DeleteObjects" } { actions_INCLUDES: "s3:*" } { actions_INCLUDES: "*" } ] principals_INCLUDES: "AWS|*" } } ] } } ] } ) {...AssetFragment} } Publicly Writable Google Cloud Buckets
Connectors
Covered asset types
Expected check: eq []
{ buckets( where: { cloudProvider: "gcp" publicAccessBlocked: false iamBindings_SOME: { OR: [ { members_INCLUDES: "allUsers" } { members_INCLUDES: "allAuthenticatedUsers" } ] role: { OR: [ { permissions_INCLUDES: "storage.objects.create" } { permissions_INCLUDES: "storage.objects.delete" } { permissions_INCLUDES: "storage.objects.update" } { permissions_INCLUDES: "storage.objects.setIamPolicy" } { permissions_INCLUDES: "storage.multipartUploads.create" } { permissions_INCLUDES: "storage.objects.*" } { permissions_INCLUDES: "storage.multipartUploads.*" } ] } } } ) {...AssetFragment} } Publicly Writable Alibaba Buckets
Connectors
Covered asset types
Expected check: eq []
{ buckets( where: { cloudProvider: "alibaba" publicAccessBlocked: false OR: [ { acl_IN: ["public-read-write"] } { bucketPolicy: { statements_SOME: { effect: "Allow" OR: [ { actions_INCLUDES: "oss:PutObject" } { actions_INCLUDES: "oss:PutObjectAcl" } { actions_INCLUDES: "oss:*" } { actions_INCLUDES: "*" } ] principals_INCLUDES: "*" } } } ] } ) {...AssetFragment} } 
