Amazon Web Services Updated SCS-C03 Exam Questions and Answers by idrees

Network ACLs arestateless, so you must allow both the outbound request and the inboundreturn traffic. For outbound TLS to an internet service on TCP443, you need an outbound allow rule permitting destination port 443. The return traffic from the internet service will come back to the instance’sephemeral port(typically in the range 1024–65535) on the inbound path. Therefore, you must allow inbound TCP traffic on the ephemeral port range to support established outbound connections.

At the same time, the requirement is todeny inbound MySQL (TCP 3306). Because NACLs process rules in order (lowest rule number first), placing an explicit deny for port 3306 as a low-numbered inbound rule ensures that traffic destined for MySQL is blocked even if there are broader allow rules later.

Option B does exactly this: it denies inbound TCP 3306 first, then allows inbound ephemeral ports for return traffic, and allows outbound TCP 443. Option A/D incorrectly allow inbound 443 (not needed for outbound-only TLS) and fail to explicitly allow ephemeral return traffic correctly. Option C allows ephemeral inbound first, and then denies 3306 later; while 3306 is not in the ephemeral range, B is the clean, canonical ordering and matches the intended stateless-return-traffic pattern most directly.

SSE-S3 uses AWS-managed keys and does not provide customer control. AWS Certified Security – Specialty documentation states that SSE-KMS with customer managed keys allows full control, auditing, and key rotation. The security engineer must first create a customer managed KMS key, then update the bucket to use SSE-KMS. Existing objects must be re-encrypted to ensure compliance.

SSE-C requires the application to manage keys, increasing complexity and risk. AWS managed keys do not meet the requirement for customer-controlled encryption.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon S3 Encryption Options

AWS KMS Customer Managed Keys

AWS Organizations and CloudFormation StackSets provide an organizational deployment mechanism for consistent infrastructure across accounts. AWS Certified Security – Specialty guidance emphasizes minimizing use of the management account and using delegated administrator capabilities where available for centralized governance while reducing blast radius. By configuring a delegated administrator account for AWS CloudFormation, the company can create and manage StackSets without performing day-to-day deployment operations from the management account. Targeting the organization root ensures the StackSet deploys to all existing accounts. Enabling automatic deployment ensures that any future accounts that join the organization (or move into targeted OUs, depending on configuration) automatically receive the monitoring service without manual intervention. This directly meets the requirement to deploy to all existing and future accounts with minimal effort. Option A requires ongoing manual updates when accounts are added, increasing operational overhead. Options C and D rely on Systems Manager Automation, which can work but introduces additional operational complexity and is not the standard AWS mechanism for organization-wide infrastructure rollout compared to StackSets with auto-deployment. StackSets also provide consistent change control, drift detection, and centralized update mechanisms, which align with governance expectations for compliance tooling.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Organizations Delegated Administration

AWS CloudFormation StackSets for Multi-Account Governance

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