SCS-C03 Dumps With Exact Questions and Answers

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

AWS KMS key policies can restrict how and when a key is used by applyingconditions such as kms:ViaService, which limits usage to requests that originate from a specific AWS service. According to the AWS Certified Security – Specialty Official Study Guide and AWS KMS documentation, the kms:ViaService condition is evaluated against the service that calls KMS on behalf of the principal.

Using StringEquals with kms:ViaService restricts usage toexactly one service endpoint. However, AWS services can invoke KMS throughservice variants, internal endpoints, or additional service integrations. When StringEquals is used, these variations can unintentionally bypass the condition, allowing the key to be used by other services through different internal service paths.

Changing the condition operator from StringEquals to StringLike ensures thatonly EC2-related service callsthat match the intended service pattern are allowed, while still preventing use by unrelated AWS services. This aligns with AWS guidance to use StringLike when service invocation patterns may vary.

Option B is incorrect because the root principal statement is required to retain administrative control over the key. Option C is invalid because changing Regions does not address unauthorized service usage. Option D does not restrict key usage and does not mitigate the issue.

AWS documentation explicitly recommendstightening condition operatorsin KMS key policies to prevent unintended service access while maintaining required functionality.

AWS Certified Security – Specialty Official Study Guide

AWS Key Management Service Developer Guide

AWS KMS Key Policy Best Practices

Amazon SQS is an AWS-managed service and does not operate within customer VPCs. Therefore, security groups and network ACLs cannot be used to control access to SQS, making options A and B invalid. According to AWS Certified Security – Specialty documentation, the recommended approach to securely access AWS services from within a VPC is throughinterface VPC endpoints (AWS PrivateLink).

By creatinginterface VPC endpoints for Amazon SQS, the company ensures that traffic to SQS stays within the AWS network and does not traverse the public internet. Adding anSQS resource policywith the aws:SourceVpce condition restricts access so that only requests originating from the specified VPC endpoint are allowed. Additionally, using the aws:PrincipalOrgId condition ensures that only principals belonging to the same AWS Organization can access the queue.

Option D introduces an external tool, increasing cost and compliance complexity, which directly violates the requirement to minimize investment outside AWS.

AWS documentation clearly identifiesVPC endpoints combined with IAM condition keysas a best practice for securing service access in multi-account environments.

AWS Certified Security – Specialty Official Study Guide

Amazon SQS Security Best Practices

AWS Organizations Documentation

AWS PrivateLink User Guide