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

AWS Systems Manager Session Manager provides secure, auditable shell access to EC2 instances without opening inbound ports. According to AWS Certified Security – Specialty guidance, Session Manager records all session activity to CloudWatch Logs or Amazon S3 and integrates with IAM Identity Center for centralized authentication.

This solution meets all requirements: no exposed ports, full audit logging, and identity-based access control. EC2 Instance Connect and serial console access do not integrate with Identity Center and may expose management paths.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Systems Manager Session Manager

AWS IAM Identity Center Integration

AWS Systems Manager Session Manager providessecure, auditable, and portless accessto EC2 instances. According to the AWS Certified Security – Specialty Study Guide, Session Manager allows administrators to connect to instanceswithout opening inbound SSH or RDP ports, fully satisfying strict compliance requirements.

Session Manager integrates directly withAWS IAM Identity Center, ensuring that all access is authenticated and authorized using centralized identity management. Additionally, Session Manager automatically records session activity and can send logs to Amazon CloudWatch Logs or Amazon S3, providing a complete audit trail of all commands executed during a session.

Option A (EC2 serial console) does not provide comprehensive auditing and is intended for recovery scenarios. Option B requires inbound network access and security group rules, violating the “no exposed management ports” requirement. Option D explicitly opens ports, which directly violates compliance constraints.

AWS documentation clearly identifiesSystems Manager Session Manager as the recommended solution for secure, auditable, and identity-integrated instance accessin regulated environments.

AWS Certified Security – Specialty Official Study Guide

AWS Systems Manager Session Manager Documentation

AWS IAM Identity Center Best Practices

Comprehensive and Detailed 100to 150 words of Explanation From AWS Certified Security – Specialty topics:

Parameter Store uses AWS KMS to encrypt SecureString parameter values when they are created or changed. When a customer managed key is used, the caller needs explicit KMS permissions, including kms:Encrypt for creating or updating SecureString values. If the application lacks that permission, the update fails. A disabled KMS key also causes failures because AWS KMS cannot perform cryptographic operations with a disabled key. A customer managed key can encrypt many SecureString parameters; existing use by another parameter is not a problem. Standard tier SecureString parameters can use customer managed keys. Using an alias instead of a key ID is also supported, so the alias is not the cause.

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A credential stuffing attack at the ALB is aLayer 7problem and is best mitigated withAWS WAF. The attacker is distributed across many IPs, so blocking by IP in a security group (Option B) is ineffective and operationally heavy. A CloudWatch alarm (Option A) only alerts; it does not block or mitigate requests.

Because the malicious traffic uses a distinctive, knownUser-Agentstring associated with a mobile device emulator, AWS WAF can quickly reduce the attack by inspecting the User-Agent header and blocking matching requests. This approach is targeted: it blocks the identified automated attack pattern while allowing legitimate users who do not present that emulator User-Agent to continue logging in. The WAF rule can be deployed immediately on the existing ALB-associated web ACL and can be further refined (for example, applied only to /login paths, combined with rate-based rules, or integrated with Bot Control) to minimize false positives.

Option D is risky because “allow only legitimate user agents” is brittle: user agents are diverse and change frequently, and a strict allow-list can accidentally block real users. Therefore, a WAF custom block rule for the known malicious User-Agent string is the correct solution.