DEA-C01 Data Ingestion and Transformation Practice Question
Exhibit
Refer to the exhibit.
{
"Version": "2012-10-17",
"Statement": [
{
"Effect": "Allow",
"Action": [
"s3:PutObject",
"s3:GetObject",
"s3:DeleteObject"
],
"Resource": "arn:aws:s3:::example-bucket/*"
},
{
"Effect": "Deny",
"Action": "s3:PutObject",
"Resource": "arn:aws:s3:::example-bucket/public/*",
"Condition": {
"StringNotEquals": {
"s3:x-amz-server-side-encryption": "AES256"
}
}
}
]
}Refer to the exhibit. A data engineer is configuring an IAM policy for a Lambda function that writes transformed data to S3. The function writes to both 'example-bucket/data/' and 'example-bucket/public/'. The policy is intended to enforce server-side encryption with SSE-S3 for all objects written to the 'public/' prefix, while allowing all operations on other prefixes. However, the Lambda function is failing with an AccessDenied error when writing to 'example-bucket/public/'. What is the most likely cause?
⚠ Common exam trap
The DEA-C01 exam often tests the nuance that bucket policies can conditionally deny operations based on request headers, and candidates mistakenly think the error is due to missing IAM permissions rather than a missing encryption header.
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 Lambda function is not setting the 'x-amz-server-side-encryption' header to 'AES256' when writing to 'public/'.
The policy enforces SSE-S3 encryption for objects written to the 'public/' prefix. When a Lambda function writes to S3 without setting the 'x-amz-server-side-encryption' header to 'AES256', the request fails with an AccessDenied error if the bucket policy requires SSE-S3. The policy explicitly denies PutObject unless the encryption header is present, so the function must include this header to succeed.
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 policy denies DeleteObject on 'public/'.
Why it's wrong here
DeleteObject is irrelevant to a write failure; the Lambda never reaches a delete operation. It is tempting because a Deny on public/ looks like the culprit, and such a statement would correctly block deletions if the requirement were to make published objects immutable.
- ✗
The policy denies PutObject on 'public/' unconditionally.
Why it's wrong here
An unconditional Deny on PutObject would block writes to public/ entirely, but the intended policy allows PutObject there subject to the SSE-S3 condition, so the failure stems from the encryption condition, not the action. It is tempting because a Deny statement is the obvious cause of AccessDenied.
- ✗
The policy does not allow GetObject for 'public/'.
Why it's wrong here
GetObject governs reads, not the PutObject call that is failing, so it cannot cause this AccessDenied. It is tempting because the policy's encryption condition applies only to writes, and GetObject would matter if the Lambda later read objects back from the public/ prefix.
- ✓
The Lambda function is not setting the 'x-amz-server-side-encryption' header to 'AES256' when writing to 'public/'.
Why this is correct
The policy's `s3:PutObject` condition requires the `x-amz-server-side-encryption` header to equal `AES256` for the `public/` prefix. Because the Lambda function omits this header, the request fails the condition and S3 returns AccessDenied, satisfying the stem's encryption-enforcement constraint.
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.