DEA-C01 Data Security and Governance Practice Question
A data engineer needs to grant an IAM user read-only access to a specific prefix (folder) in an S3 bucket. The bucket contains sensitive data. Which S3 bucket policy statement achieves this?
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
✓
{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::123456789012:user/DataEng"},"Action":"s3:GetObject","Resource":"arn:aws:s3:::mybucket/sensitive/*"}
It grants s3:GetObject for the specific prefix and denies access to other prefixes implicitly. Option A is wrong because it grants access to all objects. Option C is wrong because it uses a condition that does not restrict prefix. Option D is wrong because it grants access to all objects in the bucket.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::123456789012:user/DataEng"},"Action":"s3:GetObject","Resource":"arn:aws:s3:::mybucket"}
Why it's wrong here
Resource is the bucket itself, not objects.
- ✓
{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::123456789012:user/DataEng"},"Action":"s3:GetObject","Resource":"arn:aws:s3:::mybucket/sensitive/*"}
Why this is correct
Grants access only to objects under sensitive/ prefix.
- ✗
{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::123456789012:user/DataEng"},"Action":"s3:GetObject","Resource":"arn:aws:s3:::mybucket/*","Condition":{"StringLike":{"s3:prefix":"sensitive/"}}}
Why it's wrong here
Condition is not valid for GetObject; s3:prefix is not a condition key for GetObject.
- ✗
{"Effect":"Allow","Principal":{"AWS":"arn:aws:iam::123456789012:user/DataEng"},"Action":"s3:GetObject","Resource":"arn:aws:s3:::mybucket/*"}
Why it's wrong here
Grants access to all 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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Same concept, more angles
1 more way this is tested on DEA-C01
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A data engineer needs to grant an IAM user read-only access to an S3 bucket named 'data-lake'. Which IAM policy statement should be used?
easy- A.{"Effect":"Allow","Action":["s3:PutObject","s3:DeleteObject"],"Resource":"arn:aws:s3:::data-lake/*"}
- B.{"Effect":"Allow","Action":"s3:*","Resource":"*"}
- ✓ C.{"Effect":"Allow","Action":["s3:ListBucket","s3:GetObject"],"Resource":["arn:aws:s3:::data-lake","arn:aws:s3:::data-lake/*"]}
- D.{"Effect":"Allow","Action":"s3:ListBucket","Resource":"arn:aws:s3:::data-lake"}
Why C: It allows ListBucket on the bucket and GetObject on objects, enabling read-only access. Option A is wrong because it grants write actions (PutObject, DeleteObject). Option B is wrong because it allows all S3 actions (s3:*). Option D is wrong because it only allows ListBucket, not GetObject.
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.