Amazon Web Services SCS-C03 - AWS Certified Security – Specialty

AWS incident response best practices emphasize isolating compromised resources rather than immediately terminating them. According to AWS Certified Security – Specialty documentation, removing an instance from an Auto Scaling group prevents replacement loops, while applying a restrictive security group isolates the instance for forensic analysis.

Using Amazon EventBridge to trigger an AWS Lambda function enables automated, consistent responses to GuardDuty findings. This approach minimizes disruption to the application because healthy instances continue serving traffic while the affected instance is isolated.

Disabling credentials or modifying network ACLs can have broader impact on unrelated workloads. SNS notifications alone do not provide response automation.

AWS recommends isolate-and-investigate patterns for EC2 incident response.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon GuardDuty Automated Responses

AWS Incident Response Playbooks

AWS WAF logs contain detailed request-level information, including source IP addresses, requested URIs, and rule matches. According to AWS Certified Security – Specialty guidance, enabling AWS WAF logging provides the most reliable and tamper-resistant method to investigate web-based attacks, especially when instance-level logs are unavailable.

By streaming WAF logs through Amazon Kinesis Data Firehose to Amazon S3, the company ensures durable, centralized log storage that is independent of EC2 lifecycle events. Amazon Athena can then query the logs efficiently to identify repeated requests to the new-user-creation.php endpoint and extract attacker IP addresses.

VPC Flow Logs do not capture HTTP-level details. ALB access logs alone may not capture blocked requests. WAF logs provide the best forensic visibility for future detection.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Logging and Monitoring

Amazon Athena Log Analysis

Amazon GuardDuty is afully managed, organization-aware threat detection servicethat continuously analyzes AWS logs such as CloudTrail events, VPC Flow Logs, DNS logs, EKS audit logs, and RDS activity. According to the AWS Certified Security – Specialty Official Study Guide, GuardDuty is designed to operate atscale across AWS Organizations with minimal operational overhead.

By designating a GuardDuty administrator account in the organization’s management account and enabling GuardDuty organization-wide, the company can automatically enable threat detection across hundreds of AWS accounts. EnablingEKS Protectionallows GuardDuty to analyze Kubernetes audit logs for suspicious activity, whileRDS Protectionprovides anomaly detection for Amazon Aurora databases.

Options B, C, and D require custom log aggregation, processing, and analytics pipelines, which significantly increase operational effort and maintenance complexity. Amazon Inspector does not analyze logs, Athena-based analysis is manual, and Kinesis plus Lambda requires custom detection logic.

AWS documentation explicitly identifiesGuardDuty with AWS Organizations integrationas the recommended solution for centralized, automated threat detection across multi-account environments with minimal operational effort.

AWS Certified Security – Specialty Official Study Guide

Amazon GuardDuty User Guide

GuardDuty Organization Administration Documentation

AWS Config is a fully managed service that providescontinuous monitoring and evaluation of AWS resource configurationsagainst desired configuration baselines. According to the AWS Certified Security – Specialty Official Study Guide, AWS Config is the primary service used totrack configuration changes, evaluate compliance in near real time, and display compliance statesfor individual AWS resources.

AWS Config providesmanaged rulesthat directly map to the listed Aurora MySQL security requirements, including encryption at rest, public accessibility, deletion protection, and log exports to CloudWatch Logs. These managed rules continuously evaluate resources and mark them as compliant or noncompliant whenever a configuration change occurs.

The AWS Config dashboard enables security engineers to viewper-resource and per-rule compliance states at any point in time, satisfying the requirement to display compliance status for each part of the policy.

AWS Audit Manager (Option A) is designed for audit evidence collection and reporting, not continuous monitoring. AWS Security Hub (Option C) aggregates findings from other services but relies on AWS Config for configuration compliance data. Option D introduces unnecessary custom logic and does not provide a native compliance dashboard.

AWS documentation explicitly identifiesAWS Config as the authoritative service for continuous compliance monitoring and visibility.

AWS Certified Security – Specialty Official Study Guide

AWS Config Developer Guide

Amazon Aurora Security Best Practices

AWS Well-Architected Framework – Security Pillar

Option C is the best fit because Amazon GuardDuty provides managed threat detection forEKSby analyzingEKS control plane audit logs(EKS Protection) and correlating those signals withruntime telemetry(Runtime Monitoring) that includesprocess/OS activity, network connections, and file activityon the worker nodes. This directly matches the requirement to monitor EKS audit logsin addition tooperating system, networking, and file events to detect Kubernetes security risks.

GuardDuty produces securityfindingsfor suspicious Kubernetes behavior and runtime indicators (for example, unexpected API calls, anomalous container activity, or known malicious behaviors). To notify the security team, anAmazon EventBridgerule can match GuardDuty findings and forward them to anSNS topic. SNS supportsemail subscriptions, so the team’s mailing list can receive near-real-time alerts without building a custom log parsing pipeline.

Option A (Security Hub) aggregates findings and maps to controls/standards but does not itself provide the combined audit-log + runtime event detection described. Option B combines unrelated services and still requires custom processing. Option D only alarms on “new audit logs generated,” which does not detect “security risks” and does not include OS/network/file threat detections.

AWS Systems ManagerSession Managerprovides interactive shell access to managed instanceswithout inbound SSH,without bastion hosts, andwithout managing SSH keys. Access is controlled through IAM policies, and every session can be logged to CloudWatch Logs/S3 for auditability. This directly satisfies the “no SSH keys” requirement and reduces the network exposure surface because you can keep port 22 closed and still obtain shell access when needed.

To meet the isolation requirement, the instances can be placed in private subnets with no inbound access, and you can use Systems Manager connectivity (via SSM endpoints/agents) for administrative sessions only when required. On-premises servers can also be managed by Systems Manager by registering them as managed instances (hybrid activations), allowing the same no-SSH-key operational model across EC2 and on-prem environments.

Options A and D still require network paths and do not eliminate key management; a bastion host is additional infrastructure that must be secured and maintained. CloudShell (Option C) is an AWS-managed shell environment but does not provide a direct, managed, keyless session channel into arbitrary EC2/on-prem hosts by itself. Therefore, Session Manager is the best solution.

In IAM Identity Center, users see accounts and permission sets in the AWS access portal based onassignments. Here, the new permission set was assigned to theDevOps groupfor a specific member account. Sinceall developers except onecan see the permission set, the permission set itself and the account assignment are working correctly. The most likely cause is that the remaining developer isnot actually a memberof the DevOps group in the identity source (AWS Directory Service / Active Directory), or their group membership is not reflected due to missing/incorrect directory group assignment.

The least disruptive fix is to ensure the developer’s identity is correctly included in theDevOpsgroup within the directory. Once the user is a member of the assigned group (and after normal identity sync/refresh behavior), IAM Identity Center will evaluate the user as entitled to that permission set, and it will appear in the access portal.

Option B is unnecessary because the assignment is already effective for others. Option C is unrelated; service-linked roles for Organizations do not determine portal entitlements. Option D would not explain why only one user cannot see the permission set; if console access were misconfigured, it would affect all users assigned that permission set.

AWS Systems Manager Session Manager requires secure outbound HTTPS connectivity from the EC2 instance to Systems Manager endpoints. In a VPC without internet access, AWS Certified Security – Specialty documentation recommends using interface VPC endpoints to enable private connectivity without exposing the instance to the internet.

Creating a VPC interface endpoint for Systems Manager allows the SSM Agent to communicate securely with the Systems Manager service. The endpoint must have an attached security group that allows inbound traffic on port 443 from the VPC CIDR range. Additionally, the EC2 instance security group must allow outbound HTTPS traffic on port 443 so the agent can initiate connections.

Option C is incorrect because creating or associating key pairs enables SSH access, which can alter forensic evidence and violates forensic best practices. Option B is unnecessary because Session Manager does not require inbound rules on the EC2 instance. Option F is invalid because EC2 does not use interface endpoints for management connectivity.

This combination ensures secure, private access for forensic investigation while preserving evidence integrity and adhering to AWS incident response best practices.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Systems Manager Session Manager Architecture

AWS Incident Response and Forensics Best Practices

Amazon Detective is a managed service designed specifically toinvestigate and analyze security findingsby automatically correlating data from Amazon GuardDuty, AWS CloudTrail, and VPC Flow Logs. According to the AWS Certified Security – Specialty Official Study Guide, Detective enables security teams to identifyroot causes, anomalous behavior, and indicators of compromisethrough interactive visualizations.

Amazon Detective allows investigators to pivot directly toIAM roles, users, and resources that are involved in GuardDuty findings. Detective builds behavior graphs and timelines that show API activity, network traffic, and historical context, making it easier to understand how and why a security incident occurred.

Amazon Inspector (Option B) focuses on vulnerability scanning of compute resources and does not investigate IAM behavior. Option C requires manual analysis and lacks native visualization. AWS Security Hub (Option D) aggregates findings but does not perform root-cause investigation or behavioral analysis.

AWS documentation explicitly states thatAmazon Detective is the recommended service for deep-dive investigations following GuardDuty alerts, especially when IAM roles are involved.

AWS Certified Security – Specialty Official Study Guide

Amazon Detective User Guide

Amazon GuardDuty Integration Documentation

AWS Organizations service control policies (SCPs) are designed to enforce preventive guardrails across accounts without requiring application-level changes. According to the AWS Certified Security – Specialty documentation, SCPs can restrict specific API actions or require certain condition keys to enforce security standards centrally. AWS Lambda function URLs support two authentication modes: AWS_IAM and NONE. When the authentication type is set to NONE, the function URL becomes publicly accessible, which introduces a significant security risk in production environments.

By using an SCP that explicitly denies the lambda:CreateFunctionUrlConfig and lambda:UpdateFunctionUrlConfig actions when the lambda:FunctionUrlAuthType condition key equals NONE, the organization ensures that unauthenticated function URLs cannot be created or modified in production accounts. This enforcement occurs at the AWS Organizations level and applies automatically to all accounts within the specified organizational units (OUs). Developers are not required to change their workflows or add additional controls, satisfying the requirement of no additional developer effort.

Option A relates to browser-based access controls and does not provide authentication or authorization enforcement. Option B is not valid because AWS WAF cannot be attached directly to AWS Lambda function URLs. Option C is incorrect because SCPs do not grant permissions; they only limit permissions. AWS documentation clearly states that SCPs define maximum available permissions and are evaluated before IAM policies.

This approach aligns with AWS best practices for centralized governance, least privilege, and preventive security controls.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Organizations Service Control Policies Documentation

AWS Lambda Security and Function URL Authentication Overview