SCS-C03 Reviews Questions

Option A satisfies all requirements with the most direct, purpose-built AWS logging workflow. By using the CloudWatch Agent (or fluent-bit / unified logging configuration) on each EC2 instance—regardless of whether it is On-Demand or Spot—the application logs can be centralized into asingle Amazon CloudWatch Logs log group. Centralization ensures the logs remain available even as Spot Instances are interrupted and replaced. Access control is handled withIAM policies(and optionally resource policies/KMS encryption) so that only a specific set of users can read/query the log group.

For analysis,CloudWatch Logs Insightsprovides an interactive query language that is SQL-like and commonly treated as “SQL queries” for troubleshooting. It enables fast filtering, aggregation, and pattern detection across large log volumes without building a separate data lake pipeline. This supports event-pattern analysis and root cause investigation directly from the centralized log group.

Option B is incorrect because Logs Insights queries CloudWatch Logs data, not arbitrary log files sitting in S3. Option C is inefficient (many log groups) and Athena cannot directly query CloudWatch log groups as a native data source. Option D is incorrect because Amazon Detective is for security investigations across supported data sources and is not the primary service for ad-hoc SQL-style querying of application logs.

The Amazon CloudWatch agent requires explicit IAM permissions to create log groups, create log streams, and put log events into Amazon CloudWatch Logs. According to the AWS Certified Security – Specialty Study Guide, the most common cause of CloudWatch agent log delivery failures is missing or insufficient IAM permissions on the EC2 instance role.

The CloudWatchAgentServerPolicy AWS managed policy provides the required permissions, including logs:CreateLogGroup, logs:CreateLogStream, and logs:PutLogEvents. Attaching this policy to the EC2 instance role enables the CloudWatch agent to successfully deliver custom application logs without requiring changes to the application or logging configuration.

Options A, B, and C are incorrect because CloudTrail, Amazon S3, and Amazon Inspector are not designed to ingest custom application logs from EC2 instances in this manner. AWS documentation clearly states that IAM permissions must be granted to the EC2 role for CloudWatch Logs ingestion.

This approach aligns with AWS best practices for least privilege while ensuring reliable detection and monitoring capabilities.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon CloudWatch Logs Agent Configuration

AWS IAM Best Practices for Monitoring

To minimize downtime during future DDoS events, the company should use services that provideactive DDoS protection and rapid mitigationat scale.AWS Shield Advanced(Option B) is designed for enhanced DDoS protection for internet-facing applications. It provides expanded detection and mitigation capabilities, cost protection in certain cases, and—critically—access to theAWS DDoS Response Team (DRT)through AWS Support so the company can engage experts during an attack to reduce impact and restore availability faster.

In addition,AWS WAF(Option E) helps mitigateapplication-layer (Layer 7)attacks that often accompany DDoS events (such as HTTP floods, bot-driven abuse, and known exploit patterns). WAF can block or challenge suspicious requests, apply rate-based controls, and use managed rule groups to reduce malicious traffic before it reaches the origin, improving resilience and availability.

Option A is incorrect because GuardDuty is a detection service; it does not automatically block traffic. Option C (Flow Logs + Lambda + SG blocks) is slow and brittle for DDoS because attackers are often distributed across many IPs and can change rapidly; security group updates are not an effective DDoS mitigation strategy. Option D is more about configuration governance and remediation, not real-time DDoS traffic mitigation.

To enforce encryption in transit for Amazon S3, AWS best practice is to require HTTPS (TLS) by using a bucket policy condition that denies any request where aws:SecureTransport is false. The requirement includes both existing buckets and future buckets, so the control must continuously evaluate configuration drift and automatically remediate. AWS Config is the service intended for continuous configuration compliance monitoring across resources, and AWS Config managed rules provide standardized checks with low operational overhead. The s3-bucket-ssl-requests-only managed rule evaluates whether S3 buckets enforce SSL-only requests, aligning directly with enforcing encryption in transit. Setting the trigger type to Hybrid ensures evaluation both on configuration changes and periodically. Automatic remediation with an AWS Systems Manager Automation runbook allows the organization to apply or correct the bucket policy consistently at scale without manual work. This approach also supports governance by maintaining a measurable compliance status while actively fixing noncompliance. Option A is not the best fit because a “proactive” custom policy rule does not by itself remediate existing buckets and “block resource creation” is not how AWS Config enforces controls. Option C is incorrect because Amazon Inspector is a vulnerability management service and does not govern S3 bucket transport policies. Option D is inefficient and indirect because CloudTrail data events are not a compliance engine and would require custom processing.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Config Managed Rules for S3 Compliance

Amazon S3 Security Best Practices for SSL-only Access