SAA-C03 Design Secure Architectures Practice Question
A solutions architect is designing an S3 bucket for a mobile banking backend. The objects must never be publicly accessible, even if a developer later adds an overly broad bucket policy. What should the architect configure?
⚠ Common exam trap
It's easy for candidates to think an IAM deny policy (Option A) is sufficient, but they miss that bucket policies can be written to grant access to anonymous users independently of IAM, making S3 Block Public Access the only guaranteed safeguard.
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
✓
Enable S3 Block Public Access at the account or bucket level
S3 Block Public Access provides a definitive override that prevents any public access to objects, regardless of bucket policies or ACLs. This setting can be applied at the account or bucket level and ensures that even if a developer later adds an overly broad bucket policy, the objects remain inaccessible to anonymous users. It is the only mechanism that enforces a hard block on public access at the S3 service level.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Create an IAM policy that denies s3:GetObject to anonymous users
Why it's wrong here
IAM policies are attached to AWS identities such as users, groups, or roles; anonymous requests have no identity, so there is no IAM policy to evaluate for them. Even if you created a bucket policy with a Deny for Principal "*", that is a bucket policy, not an IAM policy, and existing public ACLs could still grant access unless explicitly overridden. Therefore this alone will not guarantee that objects in a banking bucket stay private.
- ✗
Enable S3 Transfer Acceleration
Why it's wrong here
S3 Transfer Acceleration uses globally distributed edge locations to accelerate HTTP(S) uploads to S3 over longer distances, improving speed and reducing latency for clients. It operates at the network/transport layer and changes the endpoint used, but it does nothing to change bucket permissions, object ACLs, or bucket policies. A bucket can still be publicly readable while Transfer Acceleration is enabled, so it cannot satisfy a privacy requirement.
- ✓
Enable S3 Block Public Access at the account or bucket level
Why this is correct
S3 Block Public Access provides account-level or bucket-level settings—BlockPublicAcls, IgnorePublicAcls, BlockPublicPolicy, and RestrictPublicBuckets—that override public ACLs and public bucket policies before they can take effect. For a banking backend, setting all four to true centrally at the account level ensures that no object can be exposed to the public, even if a developer accidentally adds a public ACL or bucket policy statement. This is the preferred, preventive control because it actively denies public access rather than merely detecting it.
- ✗
Enable server access logging on the bucket
Why it's wrong here
Enabling server access logging on the bucket generates detailed records of every request that is made to the bucket, storing those logs in a destination bucket so you can audit who accessed what. It is a detective control, not a preventive one: it tells you after the fact that public access occurred, but it never blocks an anonymous request. Relying on logging alone would leave the banking objects exposed to anyone with the URL until you manually revoke the access.
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
Related to this question
About these practice questions
Courseiva writes every SAA-C03 question from scratch — 935 in total, each with an explanation and a wrong-answer breakdown. None are copied from real exams or dumps. Learn why practice questions differ from exam dumps →
JA
Written by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
This SAA-C03 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 SAA-C03 exam.