SCS-C03 Exam Dumps : AWS Certified Security – Specialty

Network ACLs arestatelessand are evaluated in order based on rule number, with lower rule numbers taking precedence. According to AWS Certified Security – Specialty incident response guidance, network ACLs can be used toimmediately block traffic at the subnet levelwithout restarting instances or modifying their runtime state.

By adding a deny rule with alower priority number (10)that explicitly denies TCP traffic on port 22 from the offending IP address (10.0.1.5), the unauthorized SSH session is immediately interrupted. This approach satisfies the requirement to keep the instance running and to preserve memory for forensic analysis.

Option A violates the requirement because restarting the instance clears memory. Option C would disrupt all legitimate SSH access, not just the unauthorized session. Option D would block all internet access and could cause widespread service disruption.

AWS documentation emphasizes usingnetwork ACL deny rules for rapid, targeted containmentwhen immediate interruption is required without altering instance state.

AWS Certified Security – Specialty Official Study Guide

Amazon VPC Network ACL Documentation

AWS Incident Response Best Practices

To enforce encryption in transit to Aurora, you must require clients to useTLS/SSLwhen connecting to the database. Aurora (depending on engine flavor) supports a parameter that enforces secure transport by rejecting non-TLS connections. Setting the DB (cluster/instance) parameter such asrequire_secure_transporttoONforces clients to negotiate SSL/TLS; otherwise the server refuses the connection, ensuring all data in transit is encrypted. This directly enforces the compliance requirement at the database endpoint itself, independent of client behavior.

Kerberos authentication (Option B) provides centralized authentication and can be useful for IAM/AD integration, but it does not by itself guarantee that the network session is encrypted. Option C is incorrect because Aurora/RDS usesRDS-provided certificatesfor TLS; you don’t attach ACM certificates to Aurora the way you would for ALB/CloudFront. Option D is not the right enforcement mechanism: RDS Proxy can help with connection pooling and IAM auth patterns, but it does not inherently force all client-to-proxy or proxy-to-db connections to be encrypted in the way a DB parameter enforcement does (and you’d still need to ensure clients use TLS). Therefore, enabling the parameter that requires secure transport is the correct solution.

Cross-account access for an external auditor typically usesSTS AssumeRoleinto a role that exists in each target account. Three common failure points are: (1) therole ARNbeing wrong or missing, (2) the auditor lacking permission to callsts:AssumeRoleon that role, and (3) anexternal IDmismatch when the role trust policy requires it. Theexternal IDis a best practice for third-party access to mitigate the confused-deputy problem; if the trust policy includes an sts:ExternalId condition, the auditor must supply the exact expected value. If it’s absent or incorrect, AssumeRole will be denied.

The auditor must also be authorized on their side (IAM user/role policy) to call sts:AssumeRole (permission), and the destination role’strust policymust trust the auditor principal. If either side is misconfigured, the assume operation fails. Finally, the auditor must reference the correctrole ARNfor each account; using an incorrect ARN (wrong account ID/role name/path) is a frequent reason only “some accounts” fail.

Incorrect password (B) is irrelevant if the auditor is using API/STS federation rather than console password auth, and EC2 instance roles (D) are not required for an external auditor. Missing/incorrect secret key (E) is possible for API auth, but the question centers on cross-account role access issues; the canonical causes are external ID, AssumeRole permission, and role ARN.