DEA-C01 S3 Bucket Policy Practice Question
A data engineer needs to share a dataset stored in an S3 bucket with a partner AWS account. The partner should be able to read the data without needing to authenticate with the engineer's account. The engineer must not share any secret keys. Which approach should be used?
⚠ Common exam trap
Candidates often confuse presigned URLs with a secure long-term solution, but they are temporary and not suitable for persistent cross-account access.
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
✓
Write a bucket policy that grants access to the partner account's IAM role.
S3 bucket policies can grant cross-account access to a specific IAM role in the partner account, allowing the partner to read data without authentication or shared secrets. Option B is wrong because presigned URLs are temporary and require ongoing generation for each access, not a persistent solution. Option C is wrong because making the bucket public violates security principles and exposes data to everyone. Option D is wrong because sharing access keys is insecure and against best practices; keys should never be shared.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Write a bucket policy that grants access to the partner account's IAM role.
Why this is correct
Bucket policy can grant cross-account access securely.
- ✗
Generate presigned URLs and share them with the partner.
Why it's wrong here
Presigned URLs are temporary and require ongoing generation.
- ✗
Make the bucket publicly readable.
Why it's wrong here
Public access is not secure.
- ✗
Create an IAM user with access keys and share them with the partner.
Why it's wrong here
Sharing access keys is insecure.
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.