Free Amazon Web Services SCS-C03 Practice Exam with Questions & Answers | Set: 3

AWS CloudFormation supports the use of a service role, which allows CloudFormation to assume a dedicated IAM role to create and manage resources on behalf of users. According to the AWS Certified Security – Specialty Study Guide, using a service role is the most secure and consistent way to ensure predictable stack deployments when users have varying permission sets.

By creating a service role with cloudformation.amazonaws.com as the trusted service principal (Option B), CloudFormation—not individual users—assumes responsibility for resource creation. Updating each stack to explicitly use this service role (Option E) ensures that all deployments use the same permission set, eliminating inconsistencies.

Granting the team members permission to pass the service role via iam:PassRole (Option F) is required so that CloudFormation can assume the role during stack operations. This approach adheres to the principle of least privilege and prevents users from gaining direct access to elevated permissions.

Composite principals (Option A) are unnecessary and insecure. Referencing stack ARNs (Option C) does not solve the root cause. While Option D reflects good policy design, it is implicit in creating the service role and is not a required standalone step.

AWS documentation clearly identifies CloudFormation service roles combined with iam:PassRole as best practice for secure, consistent infrastructure deployments.

AWS Certified Security – Specialty Official Study Guide

AWS CloudFormation Service Role Documentation

AWS IAM Best Practices

Network Load Balancers operate at Layer 4 and are optimized for extreme performance, ultra-low latency, and handling sudden traffic spikes. According to AWS Certified Security – Specialty documentation, using a TCP listener on an NLB allows TLS traffic to pass through directly to backend containers without termination, preserving true end-to-end encryption.

This approach eliminates the overhead of decrypting and re-encrypting traffic at the load balancer, reducing latency and maximizing throughput. NLBs scale automatically to handle volatile traffic patterns and millions of requests per second.

Application Load Balancers operate at Layer 7 and introduce additional latency due to TLS termination and HTTP processing. Route 53 multivalue routing does not provide load balancing at the transport layer and does not ensure encryption handling.

AWS recommends NLB TCP pass-through for high-performance, end-to-end encrypted container workloads.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Elastic Load Balancing Architecture

Network Load Balancer Performance Characteristics

AWS CloudTrail organization trails are specifically designed to provide centralized, organization-wide logging with minimal operational effort. According to the AWS Certified Security – Specialty Official Study Guide, an organization trail records all management events for all member accounts and delivers them to a single Amazon S3 bucket.

To ensure that logs cannot be altered or deleted, Amazon S3 Object Lock in compliance mode must be used. Compliance mode enforces write-once-read-many (WORM) protection, meaning no user, including the root user, can delete or modify objects before the retention period expires. This directly satisfies the requirement that no changes or deletions are allowed for 2 years.

The S3 bucket must reside in the dedicated security account to provide isolation and strong security boundaries. Granting write permissions to the organization’s management account (Option A) aligns with AWS best practices, because the management account owns and manages the organization trail and centrally delivers logs on behalf of all member accounts.

Option B increases attack surface by allowing all member accounts to write directly. Option C does not meet immutability requirements because lifecycle policies do not prevent deletion. Option E introduces unnecessary services and operational complexity.

AWS documentation explicitly identifies the combination of CloudTrail organization trails + S3 Object Lock (compliance mode) as the recommended, lowest-overhead solution for long-term, immutable audit log retention.

AWS Certified Security – Specialty Official Study Guide

AWS CloudTrail Organization Trail Documentation

Amazon S3 Object Lock Documentation

AWS Well-Architected Framework – Security Pillar

Amazon Inspector provides native Lambda code vulnerability scanning. GuardDuty focuses on runtime threats, not static code analysis.

AWS WAF provides managed and custom rules that can immediately mitigate common web exploits such as SQL injection without modifying application code. According to AWS Certified Security – Specialty documentation, placing AWS WAF in front of an Application Load Balancer is a recommended rapid-response control for legacy applications with known vulnerabilities.

Creating an ALB in front of the existing EC2 instances allows seamless traffic migration. AWS WAF SQL injection rules can be deployed and tested without downtime. Updating Route 53 to point to the ALB preserves normal operations. Restricting EC2 security groups afterward prevents bypassing the WAF.

Option B introduces CloudFront changes and single-origin testing, increasing complexity. Option C cannot be completed within 24 hours and risks downtime. Option D is invalid because AWS WAF cannot be attached directly to EC2 instances.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Web ACL Architecture

AWS Application Load Balancer Security

AWS Lambda automatically sends function execution logs to Amazon CloudWatch Logs when logging is enabled in the function code. However, this logging capability depends on the Lambda execution role having the appropriate permissions. According to the AWS Certified Security – Specialty Study Guide, the execution role must include permissions such as logs:CreateLogGroup, logs:CreateLogStream, and logs:PutLogEvents.

If these permissions are missing, Lambda cannot create log groups or streams, and no execution logs will appear in CloudWatch Logs—even though the function was successfully invoked. This is the most common reason Lambda logs are unavailable during forensic investigations.

Option B is incorrect because Lambda logs are stored in CloudWatch Logs regardless of whether the invocation source is API Gateway, EventBridge, or another AWS service. Option C is incorrect because CloudWatch Logs does not require direct S3 permissions from the Lambda execution role. Option D is irrelevant because Lambda versions do not affect logging behavior.

AWS documentation emphasizes verifying execution role permissions as a first step when Lambda logs are missing.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Lambda Execution Roles

Amazon CloudWatch Logs Integration with Lambda

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

AWS incident response best practices emphasize rapid containment with minimal blast radius. According to the AWS Certified Security – Specialty Official Study Guide, isolating a compromised resource while allowing the application to continue running is the preferred initial response.

By using Amazon EventBridge to detect GuardDuty findings related to anomalous traffic and invoking a Lambda function, the security engineer can automatically remove the affected EC2 instance from the Auto Scaling group and attach a restricted security group. This immediately isolates the instance while allowing Auto Scaling to launch a replacement instance, ensuring application availability.

Option A is invalid because EC2 instance profiles do not use long-term access keys. Option C affects the entire subnet and could disrupt unrelated workloads. Option D provides notification only and does not meet the requirement for automated response.

AWS documentation explicitly recommends instance-level isolation using security groups as a best practice for initial incident containment.

AWS Certified Security – Specialty Official Study Guide

Amazon GuardDuty User Guide

AWS Incident Response Best Practices

AWS CloudTrail provides authoritative records of KMS key creation, origin, and usage. Enabling log file validation ensures tamper detection. S3 Object Lock in compliance mode enforces immutability, which is a core audit requirement cited in AWS Certified Security – Specialty materials.

CloudWatch and DynamoDB do not provide immutable storage guarantees suitable for compliance evidence.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS CloudTrail Log File Validation

Amazon S3 Object Lock

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