SCS-C02 Management and Security Governance Practice Question
A security engineer notices that an S3 bucket contains objects that are accessible to authenticated users from other AWS accounts. The bucket policy allows access to the 'aws:SourceArn' condition that references an Amazon Resource Name (ARN) from another account. What is the MOST effective way to restrict access to only users from the company's own account?
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 condition using 'aws:SourceAccount' with the company's account ID.
Using the 'aws:SourceAccount' condition key with the company's account ID ensures that only requests originating from that account are allowed, effectively blocking cross-account access from other accounts. Option A is incorrect because SCPs apply to principals within the organization and cannot restrict access from external accounts ('aws:SourceAccount' is not evaluated for SCPs). Option B is incorrect because simply removing the bucket policy would break all cross-account access but also removes any existing policy-based permissions within the account; adding IAM policies alone does not grant cross-account access and may not be the most effective solution. Option C is incorrect because 'aws:SourceArn' is typically used for service-to-service access (e.g., SNS to S3) and does not reliably restrict by account; the proper condition key for account-level restriction is 'aws:SourceAccount'.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Apply an SCP to deny s3:GetObject for any principal outside the organization.
Why it's wrong here
SCPs apply to principals within the organization, not to external principals.
- ✗
Remove the bucket policy and add an IAM policy to the company's users.
Why it's wrong here
Does not restrict access to existing objects that are already shared.
- ✗
Modify the condition to use 'aws:SourceArn' with an ARN from the company's account.
Why it's wrong here
Does not prevent other accounts from using a different source ARN.
- ✓
Add a condition using 'aws:SourceAccount' with the company's account ID.
Why this is correct
Restricts access to requests originating from the specified account.
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 SCS-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 SCS-C02 exam.