SAA-C03 Design Secure Architectures Practice Question
A partner company needs read-only access to reports in an S3 bucket for a e-learning platform. The partner has its own AWS account. What is the most secure scalable access pattern?
⚠ Common exam trap
A common mix-up: candidates choose Option B (sharing IAM user credentials) because it seems straightforward, but AWS recommends cross-account roles with bucket policies for secure, auditable, and scalable access without managing external users.
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
✓
Create a bucket policy that grants the partner role least-privilege access to the required prefix
It uses a resource-based bucket policy that grants the partner's AWS account (via its root user or an IAM role) least-privilege read-only access to a specific prefix. This approach avoids sharing long-term credentials, leverages AWS's cross-account trust mechanism, and scales securely without managing additional IAM users.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Copy the objects to a public website bucket
Why it's wrong here
Copying objects to a public website bucket exposes them through the static website endpoint, which is designed for anyone on the internet to retrieve content. It completely bypasses S3's identity- and resource-based access controls, meaning any user with the URL can read the reports. Enabling static website hosting also changes the endpoint and does not provide the granular cross-account authorization needed to limit access to a specific partner role.
- ✗
Create an IAM user in the company account and share the access keys
Why it's wrong here
Creating an IAM user in the company account and sharing access keys introduces long-term shared credentials that are difficult to rotate and monitor. Shared keys become a security liability because they cannot be scoped to a single partner role or easily revoked if the partnership ends. It violates AWS best practice of using cross-account roles with temporary credentials, and it expands the blast radius if the keys are compromised.
- ✓
Create a bucket policy that grants the partner role least-privilege access to the required prefix
Why this is correct
A bucket policy is a resource-based policy that can explicitly grant the partner's IAM role cross-account access to a specific prefix, such as s3:GetObject on arn:aws:s3:::reports/partner/*. This approach adheres to least privilege by restricting actions to only what is required (e.g., GetObject, ListBucket on that prefix) and by naming a specific external principal. It also avoids sharing long-term keys because the partner role will assume the role using its own credentials, and the policy can be updated or removed centrally by the bucket owner.
- ✗
Make the objects public and rely on difficult-to-guess object names
Why it's wrong here
Making objects public and relying on difficult-to-guess names is a form of security through obscurity, not a real access-control mechanism. S3 URLs can be leaked, shared, or brute-forced, and public objects have no authentication or authorization layer to verify who is requesting access. Even if the names are long and random, the objects are accessible to anyone who discovers the URL, so this approach does not satisfy the requirement for read-only access limited to the partner company.
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 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.