ANS-C01 Network Security, Compliance and Governance Practice Question
A company runs a multi-account AWS environment using AWS Organizations. The security team wants to enforce that all S3 buckets across all accounts are encrypted with AWS KMS and that bucket policies restrict access to specific IAM roles. They have created an SCP that denies s3:PutBucketPolicy unless the bucket is encrypted with KMS (using a condition) and restricts the PutBucketPolicy action to a specific role. After applying the SCP, the development team reports that they cannot update bucket policies even when using the allowed role. The SCP is attached to the root OU. The allowed role is in the dev account and has full S3 permissions via an IAM policy. What is the most likely reason for the failure?
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
✓
The SCP denies s3:PutBucketPolicy for all principals except the allowed role, but the SCP is applied at the root OU and affects all accounts, so the allowed role is still denied because SCPs are deny-by-default and the allow list in the SCP does not override the implicit deny.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✓
The SCP denies s3:PutBucketPolicy for all principals except the allowed role, but the SCP is applied at the root OU and affects all accounts, so the allowed role is still denied because SCPs are deny-by-default and the allow list in the SCP does not override the implicit deny.
Why this is correct
SCPs are deny-by-default. An SCP that denies an action unless a specific role is used effectively denies all other principals. But if the SCP has an Allow effect for the specific role, it still does not grant permission; it only removes the deny. However, the issue is that the SCP likely has a Deny statement with a condition that the role should not be denied, but if the condition is not met, the deny applies. The stem suggests the SCP restricts PutBucketPolicy to a specific role; if the SCP is written as a Deny for all principals except that role, it works only if the role ARN matches. The most common mistake is that the SCP uses a NotPrincipal element incorrectly, causing the deny to apply to everyone.
- ✗
The SCP must be applied to the dev account specifically, not the root OU, because SCPs attached to OUs do not affect member accounts unless explicitly inherited.
Why it's wrong here
SCPs attached to the root OU apply to all accounts in the organization. Inheritance is automatic.
- ✗
The SCP condition key for KMS encryption is incorrect because the s3:PutBucketPolicy action does not support condition keys for encryption.
Why it's wrong here
S3 actions support condition keys like s3:x-amz-server-side-encryption-aws-kms-key-id, but PutBucketPolicy does not have a condition key for encryption. However, the SCP could still evaluate conditions based on request parameters, but the condition might be invalid, causing denial.
- ✗
The IAM policy attached to the allowed role does not include s3:PutBucketPolicy permission, even though it has full S3 access.
Why it's wrong here
Full S3 access includes s3:PutBucketPolicy. If the IAM policy has S3 full access, it includes that action.
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 ANS-C01 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 ANS-C01 exam.