DEA-C01 Data Security and Governance Practice Question
A company uses Amazon EMR to process data stored in S3 with server-side encryption using AWS KMS. The EMR cluster fails with a "403 Access Denied" error when reading data from S3. The IAM role for the EMR cluster has s3:GetObject and kms:Decrypt permissions. What is the most likely issue?
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 EC2 instance profile does not have kms:Decrypt permission
Although the IAM role assigned to the EMR cluster has s3:GetObject and kms:Decrypt permissions, the EC2 instances themselves run under an instance profile (an IAM role for EC2). For S3 objects encrypted with SSE-KMS, the EC2 instance performing the read must have kms:Decrypt permission. If the instance profile lacks this permission, the request is denied with a 403 error. Option B is less likely because a bucket policy denying access would be explicit and typically not the first thing to check. Option C (EMRFS consistent view) does not affect S3 access permissions. Option D (incorrect KMS key ID) would cause a different error (e.g., 400 Bad Request or access denied for specific keys), but the primary cause is the missing kms:Decrypt on the instance profile.
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 EC2 instance profile does not have kms:Decrypt permission
Why this is correct
The instance profile must have KMS decrypt permission.
- ✗
The S3 bucket policy denies access to the EMR cluster's IAM role
Why it's wrong here
Bucket policy likely allows.
- ✗
The EMRFS consistent view is not enabled
Why it's wrong here
Consistent view is for eventual consistency, not encryption.
- ✗
The EMR cluster is using an incorrect KMS key ID
Why it's wrong here
The key ID is typically specified correctly.
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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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.