SOA-C02 Security and Compliance Practice Question
A company uses AWS Organizations to manage multiple AWS accounts. The security team requires that all Amazon S3 buckets in every account be encrypted at rest using AWS KMS customer managed keys. The SysOps administrator needs to enforce this requirement centrally without requiring changes in each account individually. Which approach should the administrator use?
⚠ Common exam trap
Watch out — candidates often confuse detective controls like AWS Config rules (which alert or remediate after the fact) with preventive controls like SCPs (which block the action at the API level), leading them to choose a reactive solution instead of the correct proactive, centrally enforced SCP.
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 service control policy (SCP) in the management account that denies creation of S3 buckets without KMS encryption
A service control policy (SCP) applied at the AWS Organizations management account can centrally deny the creation of S3 buckets that do not have AWS KMS encryption enabled, affecting all member accounts without requiring individual account changes. SCPs act as a permission guardrail that restricts what actions accounts can perform, even for account administrators, making them ideal for enforcing organization-wide security policies like mandatory KMS encryption on S3 bucket creation.
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 in each account that denies creation of unencrypted S3 buckets
Why it's wrong here
IAM policies are identity-based and only affect the specific IAM users, groups, or roles they are attached to within a single account; they do not apply to the AWS account root user or to principals in other accounts. An administrator would have to manually attach a deny policy to every user, group, and role in every member account, and any new account or role added later would be unprotected. This is an operational burden and lacks the centralized enforcement that an SCP provides at the organization level, so it does not reliably prevent creation of unencrypted buckets across all accounts.
- ✗
Configure an S3 bucket policy on each bucket to require encryption
Why it's wrong here
Bucket policies are resource-based policies attached to an existing S3 bucket, so they can control access to an already-created bucket but cannot intercept the s3:CreateBucket API call at all. The action to create a bucket is invoked before the bucket exists, meaning there is no bucket policy to evaluate at that time. Additionally, bucket policies only apply to the specific bucket and to the requests made against it, not to the creating principal or other accounts' ability to create new buckets, so they cannot enforce a default encryption requirement at creation.
- ✓
Create a service control policy (SCP) in the management account that denies creation of S3 buckets without KMS encryption
Why this is correct
An SCP in the management account is the correct preventive control because AWS Organizations applies SCPs to all member accounts, OUs, and their principals, including the root user. The SCP can deny s3:CreateBucket unless the request includes the condition key s3:x-amz-server-side-encryption-aws-kms, forcing all new buckets to use SSE-KMS. Because SCPs are evaluated before the API call is allowed, they stop the bucket from being created at all, giving central management of encryption policy across the entire organization.
- ✗
Enable AWS Config rules in each account to detect and remediate non-compliant buckets
Why it's wrong here
AWS Config rules are detective controls that run after a resource is created, evaluating whether the bucket is compliant, and even automated remediation using SSM automation still happens after the fact. Each account must have AWS Config enabled and the rule deployed in every region, requiring an aggregation setup for central visibility, and this does not block the CreateBucket call. Therefore, it can detect and correct a non-compliant bucket but cannot prevent the temporary existence or the violation from occurring in the first place.
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 SOA-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 SOA-C02 exam.