DEA-C01 Data Store Management Practice Question
A retail company stores customer transaction data in an Amazon S3 bucket. The data is encrypted using server-side encryption with AWS KMS (SSE-KMS). The company uses an IAM role to allow an Amazon Athena query service to read the data. The data engineer creates a new Athena workgroup and attempts to run a query on the S3 bucket. The query fails with an access denied error. The IAM role has permissions to decrypt the KMS key and read from the bucket. The engineer checks the S3 bucket policy and finds that it does not explicitly allow access. What is the most likely cause of the failure?
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
✓
The S3 bucket policy does not grant the required permissions to the Athena service principal.
The most likely cause is that the S3 bucket policy does not explicitly grant the required permissions to the Athena service principal. Even though the IAM role has permissions to decrypt and read, Athena operates as a service and the bucket policy must allow the `athena.amazonaws.com` principal to perform `s3:GetObject` and `s3:ListBucket` actions. Option B is correct because without this explicit grant, the bucket policy implicitly denies access. Option A is incorrect because the bucket being in a different account would cause an error, but the scenario does not indicate cross-account setup. Option C is incorrect because the IAM role already has decrypt permissions. Option D is incorrect because Athena supports SSE-KMS encrypted data with proper KMS permissions.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
The S3 bucket is in a different AWS account than the Athena workgroup.
Why it's wrong here
There is no mention of cross-account; the role is likely in the same account.
- ✓
The S3 bucket policy does not grant the required permissions to the Athena service principal.
Why this is correct
The S3 bucket policy must explicitly allow the Athena service or the IAM role to access the bucket.
- ✗
The IAM role does not have permission to use the KMS key for encryption operations.
Why it's wrong here
The role has decrypt permissions, which is sufficient for reading.
- ✗
Athena does not support querying data encrypted with SSE-KMS.
Why it's wrong here
Athena supports SSE-KMS encrypted data.
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.