SOA-C02 Security and Compliance Practice Question
A SysOps administrator needs to ensure that data in an S3 bucket is encrypted at rest. The bucket already has server-side encryption with S3 managed keys (SSE-S3) enabled. Which additional step is required to enforce encryption for all objects?
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
✓
Add a bucket policy that denies PutObject without encryption.
A bucket policy can deny PutObject requests that do not include the x-amz-server-side-encryption header, thereby enforcing encryption for all uploads. Option B is incorrect because CloudTrail logs API calls but does not enforce encryption. Option C is incorrect because enabling default encryption on the bucket only encrypts objects that are uploaded without specifying encryption, but it does not prevent unencrypted uploads; a bucket policy is needed to enforce encryption. Option D is incorrect because versioning allows multiple versions of objects but does not enforce encryption.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
Add a bucket policy that denies PutObject without encryption.
Why this is correct
This enforces encryption at upload time by explicitly rejecting any PutObject request that does not include server-side encryption headers (e.g., x-amz-server-side-encryption: AES256 or aws:kms). This is a preventive control that blocks unencrypted writes outright, unlike default encryption which merely applies encryption if the request lacks headers but can be overridden by explicit headers. The policy should include a condition like "Null": {"s3:x-amz-server-side-encryption": "true"} to deny requests without the encryption header.
- ✗
Enable CloudTrail to log unencrypted uploads.
Why it's wrong here
CloudTrail is an auditing service that records API calls for governance and security analysis; it does not intercept or block S3 operations. While it would provide a record of unencrypted PutObject calls, enabling it after the fact only documents the violation and does not prevent the data from being written in plaintext. The requirement to "ensure that data in S3 is encrypted" demands a preventive enforcement, not detective logging.
- ✗
Enable default encryption on the bucket.
Why it's wrong here
Default encryption is already enabled per the scenario, and it only applies server-side encryption when the upload request does not specify encryption headers. An explicit PutObject with encryption set to None or without headers can still bypass default encryption because default encryption is applied only when the request lacks any encryption settings. Thus it does not guarantee that every object is encrypted; a bucket policy with a deny condition is needed to enforce encryption at all times.
- ✗
Enable versioning on the bucket.
Why it's wrong here
Versioning maintains multiple versions of an object and protects against accidental deletion/overwrites, but it has no effect on encryption. Enabling versioning does not inspect or modify the encryption status of uploaded objects; unencrypted objects remain unencrypted across all versions. Versioning is a data lifecycle feature, not a security control, and therefore fails to enforce encryption.
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 |
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JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SOA-C02 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 SOA-C02 exam.