SCS-C02 Security Logging and Monitoring Practice Question
A security engineer notices that an Amazon S3 bucket has been accessed from an IP address outside the company's allowed range. The engineer needs to identify the IAM user who made the request. Which AWS service should be used to find this information?
⚠ Common exam trap
Many candidates confuse S3 server access logs with CloudTrail, assuming that server access logs include IAM user details, when in fact they only log the requester's AWS account ID or anonymous access, not the specific IAM user identity.
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
✓
AWS CloudTrail
AWS CloudTrail is the correct service because it records all API calls made to AWS services, including S3 operations, and captures the identity of the IAM user or role that made the request. By examining CloudTrail logs, the security engineer can find the specific IAM user associated with the source IP address that accessed the bucket, as CloudTrail logs include both the user identity and the source IP address for each event.
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 server access logs
Why it's wrong here
These logs record object-level requests like bucket/object operations, with fields such as requester, bucket key, and response time, but the requester field often shows an anonymous or authenticated user's canonical ID, not the IAM user's ARN. They lack fine-grained IAM identity and governance data like source IP, user agent, and API parameters, and they're opt-in at bucket level, so they don't capture management-plane actions like bucket configuration changes.
- ✓
AWS CloudTrail
Why this is correct
CloudTrail captures management-plane and (with data events) object-level API calls. Each event includes the IAM user, role, or federated user that made the request, along with source IP, access key, timestamp, and request/response details. For S3, enabling data events on the bucket records GetObject/PutObject with full caller identity, making it the definitive audit source for identifying which IAM principal performed an action.
- ✗
VPC Flow Logs
Why it's wrong here
VPC Flow Logs capture IP traffic going to and from elastic network interfaces, recording the five-tuple (source/destination IP, ports, protocol), packets/bytes, and allow/deny action. They do not correlate traffic to IAM users or API operations at all; a connection from an EC2 instance to S3 would show the instance's private IP, not the IAM user or role, and S3 requests are typically encrypted over HTTPS. They are useful for network diagnostics, not identity forensics.
- ✗
Amazon CloudWatch Logs
Why it's wrong here
CloudWatch Logs is a log storage and monitoring service that can ingest logs from various sources—application logs, OS syslogs, or forwarded CloudTrail events—but it has no native mechanism for recording who called an S3 API. It cannot generate API events on its own, and without an upstream source like CloudTrail, it contains no IAM principal information. Searching CloudWatch Logs would reveal caller identity only if you separately configured a pipeline to deliver CloudTrail events there.
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.