DEA-C01 Data Security and Governance Practice Question
Which TWO actions should a data engineer take to protect sensitive data in an Amazon S3 bucket from being accessed by unauthorized users? (Select TWO.)
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Add a bucket policy with a Deny effect for unauthorized principals
Option C is correct because an S3 bucket policy with an explicit Deny effect overrides any Allow in IAM or bucket policies, so it reliably blocks the specified unauthorized principals from accessing the sensitive objects. Option E is correct because S3 Block Public Access settings prevent public ACLs and public bucket policies from exposing the bucket, closing off the most common accidental data-exposure path. Options A, B, and D do not restrict access: a VPC endpoint only controls how traffic reaches S3 (not who is authorized), server access logging only records requests after they occur, and CloudTrail only provides audit logging of API activity rather than preventing unauthorized access.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create a VPC endpoint for S3
Why it's wrong here
A VPC endpoint keeps traffic to S3 on the AWS private network, but it does not authenticate or authorise callers; anyone with valid credentials and a permitted route can still read the objects. It is the right choice when the requirement is avoiding internet egress or NAT costs for private-subnet workloads.
- ✗
Enable S3 server access logging
Why it's wrong here
Server access logging records requests after they occur, providing an audit trail rather than blocking access, so it cannot prevent unauthorised reads. It is genuinely useful for forensic analysis, billing reconciliation or detecting anomalous access patterns, and would be the right choice when the requirement is visibility into who accessed objects, not enforcement.
- ✓
Add a bucket policy with a Deny effect for unauthorized principals
Why this is correct
A bucket policy with a Deny effect explicitly overrides any Allow granted elsewhere, including IAM policies, so unauthorised principals are blocked regardless of other permissions. This directly satisfies the requirement to prevent access by unauthorised users.
- ✗
Enable AWS CloudTrail for the bucket
Why it's wrong here
CloudTrail captures S3 data-plane API calls for auditing after the fact; it enforces no authorisation decision, so unauthorised principals are still served. It is the correct choice when the requirement is recording object-level API activity across accounts for compliance or incident investigation, rather than preventing the access itself.
- ✓
Enable S3 Block Public Access
Why this is correct
S3 Block Public Access overrides bucket policies and ACLs that would otherwise grant public access, blocking anonymous and public principals at the account or bucket level. This enforces the constraint that unauthorised users cannot reach the sensitive objects.
Quick reference
AWS S3 Storage Class Comparison
| Storage Class | Min Duration | Retrieval | Use Case |
|---|---|---|---|
| S3 Standard | None | Immediate | Frequently accessed data |
| S3 Standard-IA | 30 days | Immediate | Infrequent access, rapid retrieval |
| S3 One Zone-IA | 30 days | Immediate | Non-critical infrequent data |
| S3 Intelligent-Tiering | None | Immediate–hours | Unknown or changing access patterns |
| S3 Glacier Instant | 90 days | Milliseconds | Archive with instant retrieval |
| S3 Glacier Flexible | 90 days | Minutes–hours | Archive, flexible retrieval |
| S3 Glacier Deep Archive | 180 days | Hours | Long-term compliance archive |
Go deeper
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This DEA-C01 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the DEA-C01 exam.