A research institution is storing highly sensitive genomic data in Amazon S3. This data must adhere to strict data classification standards, requiring that access be granted only to specific researchers for specific projects, and only from within authorized VPCs. Furthermore, the data must never be exposed to the public internet. How can the institution enforce these granular access controls and network isolation for the S3 bucket?
- AImplement AWS PrivateLink for S3 access, and use an S3 Bucket Policy with conditions on `aws:sourceVpce` and IAM policies restricting principals.
- BUtilize AWS WAF to filter incoming requests to S3, and integrate with AWS Organizations for account-level restrictions.
- CUse S3 Bucket Policies to restrict access based on IP addresses, and enable S3 Object Lock for immutability.
- DApply IAM policies to users/roles, and configure VPC Endpoints for S3 to restrict access to authorized VPCs.
Show answer & explanationAnswer & explanation
Correct answer: A. Implement AWS PrivateLink for S3 access, and use an S3 Bucket Policy with conditions on `aws:sourceVpce` and IAM policies restricting principals.
AWS PrivateLink for S3 (via a Gateway VPC Endpoint) ensures that traffic to S3 stays within the AWS network and does not traverse the public internet, satisfying network isolation. An S3 Bucket Policy with a condition like `aws:sourceVpce` ensures that access to the bucket is only allowed from specific VPC endpoints. Combined with IAM policies restricting which principals (users/roles) can access the data, this provides granular access control and prevents public exposure.
Why the other options are wrong
- B. AWS WAF protects web applications and APIs at the edge; S3 buckets primarily use S3 access controls directly. AWS Organizations provides account-level restrictions but doesn't specifically enforce network isolation for S3 access at the bucket level.
- C. S3 Object Lock is for immutability, not access control. Restricting by IP addresses is less robust than VPC endpoint conditions, especially for internal AWS services, and doesn't guarantee traffic never hits the public internet if a public endpoint is used.
- D. While IAM policies control user/role access, and VPC Endpoints (Gateway or Interface) allow private access to S3, the `aws:sourceVpce` condition in a bucket policy is essential to *enforce* that access *must* come via a specific endpoint, not just allow it. Without this, direct internet access could still be possible if not explicitly denied.
S3 Access via VPC Endpoint with Bucket Policy
Accessing S3 via a VPC Endpoint ensures that traffic remains within the AWS network, never traversing the public internet. An S3 Bucket Policy can then enforce that access is only permitted if it originates from a specific VPC Endpoint, providing network isolation and granular control.
- VPC Endpoints for S3: Gateway (free) or Interface (PrivateLink, paid).
- Gateway endpoints are for S3 and DynamoDB only.
- Bucket policies with `aws:sourceVpce` condition enforce endpoint usage.
- Prevents public internet exposure for S3 access.
Memory trick: Route S3 through the 'VPC Gate' and 'Policy Guard' it.