AWS WAF string match rule statements allow inspection of HTTP headers, including the User-Agent header. According to AWS Certified Security – Specialty guidance, when malicious traffic can be uniquely identified by a consistent request attribute, such as a device-specific user agent, a string match rule provides precise mitigation with minimal false positives.

IP-based blocking is ineffective for globally distributed botnets. Geographic blocking risks denying access to legitimate users. Rate-based rules limit request volume but do not prevent low-and-slow attacks.

By matching the unique IoT device brand in the User-Agent header, the security engineer can block only malicious requests while preserving customer access.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Rule Statements

AWS DDoS Mitigation Best Practices

AWS KMS keys are strictly regional resources. According to AWS Certified Security – Specialty documentation, a KMS key created in one Region cannot be used to encrypt or decrypt data in another Region. This includes encrypted RDS and Aurora snapshots.

When copying an encrypted snapshot to a different Region, the destination Region must have its own KMS key. AWS automatically re-encrypts the snapshot using the specified KMS key in the destination Region during the copy operation.

Options C and D are invalid because IAM policies cannot extend a KMS key’s scope across Regions. Option A is incorrect because Secrets Manager does not store or manage KMS keys themselves.

AWS best practices require creating a new customer managed key in the target Region and using it during the snapshot copy process.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS KMS Regional Key Limitations

Amazon RDS Encrypted Snapshot Copy

The immediate containment step for exposed access keys is todisable (deactivate) the compromised IAM access key(Option B). This prevents any further use of the leaked credentials, which is essential once secrets are publicly exposed. Creating a new key (Option D) may be part of recovery later, but it does not stop abuse of the already exposed key unless the exposed key is first deactivated.

To determine whether the credentials were used, you need evidence of access activity. Among the provided options, the best fit is generating and reviewing theIAM credential report(Option E). The report includes metadata such as access key status and “last used” style details that help triage whether the user’s credentials have been exercised recently. While deeper investigation would typically rely on CloudTrail “AccessKeyId” searches, the credential report is a quick AWS-native step aligned to the answer choices.

Option A is not correct: IAM Access Analyzer helps identify external access paths to resources and validate policies; it does not provide a definitive history of what a specific access key did. Option C is not a GuardDuty capability—GuardDuty generates findings; it does not “block” a specific access key. Therefore, deactivating the key and using credential reporting to assess recent usage best matches the requirements.