SAA-C03 Design Secure Architectures Practice Question
A company must share an S3 bucket with a third-party vendor. The vendor has their own AWS account. What is the most secure method to grant the vendor access to the S3 bucket?
⚠ Common exam trap
SAA-C03 often tests the difference between long-term IAM user credentials and temporary role-based access, and candidates may incorrectly choose sharing access keys as a simpler solution without recognizing the security risks.
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 cross-account IAM role for the vendor to assume.
Creating a cross-account IAM role allows the vendor to assume a role in the company's account using their own credentials, granting temporary, scoped access to the S3 bucket without sharing long-term credentials. This follows AWS security best practices for least privilege and credential management. It is the most secure method because no permanent secrets are exchanged.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Share the company's IAM user credentials with the vendor.
Why it's wrong here
Sharing credentials is a major security violation. It circumvents all auditability, is impossible to rotate effectively, and gives the vendor permanent access that cannot be easily scoped or revoked. This approach is highly insecure and should never be used in any production environment under any circumstances.
- ✗
Create an IAM user for the vendor and share the access keys.
Why it's wrong here
Creating an IAM user for a third party creates long-lived credentials that must be managed, rotated, and secured. This adds unnecessary administrative overhead and increases the risk of credential leakage. Cross-account roles are the preferred AWS architectural pattern because they rely on temporary, session-based tokens instead of static keys.
- ✓
Create a cross-account IAM role for the vendor to assume.
Why this is correct
A cross-account role provides a secure, temporary, and audited method for external access. The vendor assumes the role using their own credentials, which AWS then swaps for temporary security tokens. This provides the company with full control over the permissions assigned to the role and the duration of access.
- ✗
Make the S3 bucket public and restrict by IP address.
Why it's wrong here
Making a bucket public is a high-risk security posture, regardless of IP restrictions. IP-based filtering is easily bypassed by spoofing or VPNs and does not provide authentication. This method fails to meet modern security standards and risks accidental data exposure if the bucket policy is misconfigured or updated.
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 |
About these practice questions
One of 149 original SAA-C03 practice questions on Courseiva, each with a full explanation and wrong-answer analysis — not exam dumps or protected exam content. Learn why practice questions differ from exam dumps →
JA
Written and reviewed by Johnson Ajibi, MSc IT Security
Senior Network & Security Engineer · founder of Courseiva
Last reviewed September 2026 · checked against the official Amazon Web Services exam blueprint
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.