SCS-C02 Security Logging and Monitoring Practice Question
A company uses AWS Organizations and wants to centralize security logs from all member accounts into a single S3 bucket in the management account. The bucket policy allows only the management account's root user to write objects. However, logs are not being delivered from member accounts. What is the MOST likely cause?
⚠ Common exam trap
The trap here is that candidates often overlook that the bucket policy's explicit denial to all principals except the management account root user also blocks the logging service's cross-account write attempts, even though the service is not a user but an AWS service principal.
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 bucket policy denies write access to all principals except the management account's root user, preventing cross-account writes.
The bucket policy explicitly restricts write access to only the management account's root user. For cross-account log delivery from member accounts, the policy must grant write permissions to the logging service (e.g., AWS CloudTrail or AWS Config) in each member account. Without such permissions, the service cannot write objects to the bucket, causing log delivery to fail.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
S3 Transfer Acceleration is not enabled.
Why it's wrong here
Transfer Acceleration is an optimization that routes uploads through CloudFront edge locations to speed transfers over the public internet; it is not an authorization or security feature. CloudTrail and similar logging services deliver objects over AWS's internal network using S3 APIs, so enabling or disabling it has no effect on log delivery. Even if Transfer Acceleration were enabled, the bucket policy's explicit denial would still prevent the logging service from writing, so it cannot explain the failure.
- ✗
VPC endpoints are not configured for the logging service.
Why it's wrong here
VPC endpoints provide private connectivity between a VPC and AWS services, but the logging service such as CloudTrail is AWS-managed and delivers objects to S3 without requiring a VPC endpoint. An S3 VPC endpoint is only necessary if the bucket policy restricts access to a specific endpoint or if the logging service must route through your VPC, neither of which is described here. Because the bucket remains reachable from the AWS network and the failure is caused by an explicit bucket policy denial, the absence of a VPC endpoint is unrelated.
- ✗
The S3 bucket uses an AWS KMS key, and the key policy does not grant decrypt permissions to the logging service.
Why it's wrong here
If the S3 bucket uses SSE-KMS, the customer managed key policy must grant the logging service permissions such as kms:GenerateDataKey and kms:Decrypt, so a KMS misconfiguration could prevent uploads if encryption fails. However, the scenario states the bucket policy explicitly denies write access to all principals except the management account's root user; this explicit Deny blocks s3:PutObject before any encryption step occurs. No KMS permission would help when the service principal has already been denied the fundamental write action required to deliver the log object.
- ✓
The bucket policy denies write access to all principals except the management account's root user, preventing cross-account writes.
Why this is correct
To centralize security logs in a management account bucket, the bucket policy must explicitly allow the logging service principal, such as cloudtrail.amazonaws.com, to write objects on behalf of member accounts. If the bucket policy denies s3:PutObject to all principals except the management account root user, every delivery attempt from a member account is a cross-account write and is denied. Service principals are not the root user and never inherit the account root's permissions, so this restrictive bucket policy exactly prevents central log delivery.
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 |
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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.