SCS-C02 Threat Detection and Incident Response Practice Question
A security engineer is configuring an automated incident response workflow. When a GuardDuty finding of type 'UnauthorizedAccess:EC2/SSHBruteForce' is generated, the workflow should isolate the EC2 instance and snapshot its EBS volume. Which AWS service can coordinate these actions?
⚠ Common exam trap
Many candidates confuse Lambda's ability to run code with the need for orchestration, overlooking that Step Functions provides the necessary state management, sequencing, and error handling for multi-step incident response workflows.
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 Step Functions
AWS Step Functions is the correct service because it is designed to orchestrate multi-step workflows by coordinating AWS services like Lambda, EC2, and EBS snapshots in a defined state machine. For the given GuardDuty finding, Step Functions can receive the event, invoke a Lambda function to isolate the EC2 instance (e.g., modify security groups or attach a deny-all NACL), and then trigger another Lambda or direct API call to snapshot the EBS volume, all with built-in error handling, retries, and sequencing.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
AWS Lambda functions invoked sequentially
Why it's wrong here
Chaining AWS Lambda functions sequentially hard-codes the workflow in application code, requiring you to build custom retry, error handling, and state persistence for each step. Because each function must know its predecessor and successor, adding a branch or waiting for human approval means refactoring the entire invocation chain. Step Functions, by contrast, natively provides state management, timeouts, and retries, making it the appropriate orchestration layer for an incident response pipeline.
- ✓
AWS Step Functions
Why this is correct
AWS Step Functions is the correct choice because it models incident response as a state machine, allowing you to coordinate Lambda, ECS, SNS, DynamoDB, and other services with explicit transitions, choice states, and parallel branches. Its durable execution records the state of each step, and built-in retry/timeout policies handle transient failures, while Standard Workflows support long-running processes such as waiting for a security analyst to approve a containment action. This gives you auditable, repeatable automation that remains maintainable as the response plan evolves.
- ✗
AWS CloudFormation
Why it's wrong here
AWS CloudFormation is an infrastructure-as-code service that provisions and updates AWS resources from a template; it has no runtime event-driven orchestration capability to execute incident response procedures. While you could use CloudFormation to deploy the Step Functions state machine and its IAM roles, the service itself does not respond to findings or drive a sequence of actions after deployment. Therefore it is a supporting tool for building the automation, not the workflow executor the security engineer needs.
- ✗
AWS Config rules with auto-remediation
Why it's wrong here
AWS Config rules with auto-remediation are designed for compliance checks that trigger a single Systems Manager Automation document, such as 'stop instance' or 'enable encryption,' not for multi-step incident response playbooks. They lack the native decision branching, human approval gates, and service-to-service coordination that a full response workflow requires, and they are evaluated against resource compliance rather than event-driven threat signals. For complex response actions, the orchestration should live in Step Functions, with Config rule remediation reserved for simple, deterministic fixes.
Quick reference
Cloud Service Model Comparison
| Model | You Manage | Provider Manages | Examples |
|---|---|---|---|
| IaaS | OS, runtime, apps, data | Hardware, hypervisor, networking | EC2, Azure VMs, GCP Compute Engine |
| PaaS | Apps and data | OS, runtime, middleware, hardware | Elastic Beanstalk, Azure App Service |
| SaaS | Data and settings only | Everything else | Microsoft 365, Salesforce, Workday |
| FaaS / Serverless | Function code only | Infra, scaling, runtime | Lambda, Azure Functions, Cloud Run |
| CaaS | Containers and apps | Kubernetes, OS, hardware | EKS, AKS, GKE |
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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.