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

The fastest, least-effort way to mitigate SQL injection at the edge—without modifying legacy application code—is to place the application behind a component that supportsAWS WAFand applymanaged SQL injection protections. AnApplication Load Balancerintegrates directly with AWS WAF, allowing the security engineer to deploy a web ACL (including AWS Managed Rules for SQL injection and custom patterns based on the provided samples) and immediately start blocking malicious payloads before they reach the EC2 instances and the database.

Option A also preserves normal operations during rollout: you can create the ALB, register the existing EC2 instances as targets, validate health checks and traffic behavior, apply WAF protections, and then shift Route 53 weighted records to the ALB with minimal downtime. Finally, tightening the EC2 security groups to prevent direct internet access ensures all inbound web traffic is forced through the ALB + WAF inspection point, reducing exposure quickly.

Option B is risky because it uses only one EC2 origin (reducing availability) and adds CloudFront origin configuration complexity under a 24-hour deadline. Option C requires code changes on unsupported software and is unlikely to be safely delivered in time. Option D is invalid because AWS WAF cannot be attached directly to EC2 instances, and changing DB-port exposure doesn’t address SQL injection on the web layer.

AWS WAF allows security engineers to createstring match rule statementsthat inspect specific parts of web requests, including HTTP headers such as theUser-Agentheader. According to the AWS Certified Security – Specialty Study Guide and AWS WAF documentation, string match rules are ideal for blocking requests that contain known malicious identifiers, such as a distinctive user agent associated with a specific bot or IoT device brand.

In this scenario, the attack originates from a specific IoT device brand that uses aunique user agent. A string match rule that inspects the User-Agent header can precisely block malicious requests while allowing legitimate customer traffic to continue uninterrupted. This approach provides targeted mitigation for both current and future attacks originating from the same device signature.

Option A is incorrect because IP addresses cannot be derived from user agent strings, and IoT botnets frequently rotate IP addresses, making IP-based blocking ineffective. Option B is incorrect because geographic blocking is overly broad and risks blocking legitimate customers in the same regions as the attacking devices. Option C is incorrect because rate-based rules limit request volume per IP address and do not specifically identify malicious device signatures; legitimate high-traffic users could be unintentionally blocked.

AWS documentation emphasizes thatheader inspection with string match conditionsis a best practice for mitigating attacks that use identifiable request characteristics such as custom user agents, especially in DDoS and bot mitigation scenarios.

AWS Certified Security – Specialty Official Study Guide

AWS WAF Developer Guide – Rule Statements

AWS DDoS Resiliency Best Practices

AWS Well-Architected Framework – Security Pillar

To addresssoftware vulnerabilities, you need both (1) a vulnerability assessment capability and (2) a consistent patching mechanism.Amazon Inspectorcontinuously scans EC2 instances for known software vulnerabilities and exposures (CVEs), package-level issues, and security misconfigurations relevant to the supported scan types. It provides prioritized findings and helps the security team understand which instances are exposed and why.

To mitigate those vulnerabilities,AWS Systems Manager Patch Managerprovides automated, policy-driven patching for fleets of EC2 instances. Patch Manager can schedule patch windows, control reboots, enforce baselines, and report compliance, allowing the company to remediate issues at scale with controlled operational impact.

Option B focuses on firewall/AV tooling, which can be helpful, but it is not a complete vulnerability detection-and-patching solution and is heavier to manage across large fleets. Option C is centered on log anomaly detection, not vulnerability management. Option D mixes GuardDuty Malware Protection (malware detection) with patching; GuardDuty is not a vulnerability scanner and does not replace Inspector for CVE detection. Therefore, Inspector + Patch Manager is the correct combined solution to detect and mitigate software vulnerabilities.

AWS networking best practices require private subnets to access the internet only through NAT gateways located in public subnets. According to the AWS Certified Security – Specialty Study Guide, NAT gateways must be provisioned in public subnets and used as the default route for outbound traffic from private subnets.

Verifying NAT gateways in each Availability Zone ensures high availability and fault tolerance. Updating the private subnet route tables to send 0.0.0.0/0 traffic to the NAT gateway prevents direct internet access while allowing outbound connectivity.

Routing private subnet traffic directly to an internet gateway violates subnet isolation principles. NAT gateways must never be placed in private subnets.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon VPC Routing and NAT Gateways

AWS Network Segmentation Best Practices