Amazon Macie is the AWS service designed specifically to discover, classify, and report sensitive data stored in Amazon S3. According to the AWS Certified Security – Specialty Study Guide, Macie uses machine learning and managed data identifiers to automatically detect sensitive data types such as PII and financial information.

Macie integrates natively with Amazon EventBridge, allowing findings to be routed to other services such as Amazon SNS with minimal configuration. Creating an EventBridge rule to forward Macie findings to an existing SNS topic satisfies the notification requirement without custom code.

Option A is invalid because AWS Config does not inspect object contents. Option B requires custom development and ongoing maintenance. Option D is incorrect because Amazon GuardDuty focuses on threat detection, not sensitive data discovery.

AWS documentation emphasizes Macie as the lowest-effort and most accurate solution for sensitive data identification in S3.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Amazon Macie Sensitive Data Discovery

Amazon EventBridge Integration with Security Services

AWS KMS provides condition keys that can be used to tightly scope how and where a customer managed key can be used. According to the AWS Certified Security – Specialty Study Guide, the kms:ViaService condition key is specifically designed to restrict key usage to requests that originate from a particular AWS service in a specific Region.

By configuring the key policy to allow KMS cryptographic operations only when kms:ViaService equals s3..amazonaws.com, the security engineer ensures that the key can be used exclusively by Amazon S3. Even if other IAM principals have permissions to use the key, the key cannot be used by other services such as Amazon EC2, Amazon RDS, or AWS Lambda.

Option A is incorrect because AWS services do not assume identities in key policies. Options C and D modify IAM role policies, which do not control how a KMS key is used by AWS services. AWS documentation clearly states that service-level restrictions must be enforced at the KMS key policy level using condition keys.

This approach enforces strong separation of duties and limits blast radius, which aligns with AWS security best practices.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS KMS Key Policy Condition Keys

AWS KMS Best Practices

AWS Config is the AWS service designed to continuously evaluate resource configurations against defined rules. According to the AWS Certified Security – Specialty Study Guide, AWS Config managed rules exist specifically to check database encryption, public accessibility, deletion protection, and log exports for Amazon RDS and Aurora.

AWS Config provides a real-time compliance timeline and displays the compliance state of each resource against each rule at any point in time. This granular visibility is required to assess ongoing compliance with security policies.

Audit Manager generates reports but does not provide continuous compliance monitoring. Security Hub aggregates findings but does not track configuration drift. EventBridge and Lambda introduce unnecessary complexity.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS Config Managed Rules for RDS

AWS Continuous Compliance Monitoring

AWS WAF logs contain detailed request-level information, including source IP addresses, requested URIs, and rule matches. According to AWS Certified Security – Specialty guidance, enabling AWS WAF logging provides the most reliable and tamper-resistant method to investigate web-based attacks, especially when instance-level logs are unavailable.

By streaming WAF logs through Amazon Kinesis Data Firehose to Amazon S3, the company ensures durable, centralized log storage that is independent of EC2 lifecycle events. Amazon Athena can then query the logs efficiently to identify repeated requests to the new-user-creation.php endpoint and extract attacker IP addresses.

VPC Flow Logs do not capture HTTP-level details. ALB access logs alone may not capture blocked requests. WAF logs provide the best forensic visibility for future detection.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

AWS WAF Logging and Monitoring

Amazon Athena Log Analysis

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

Network Load Balancers operate at Layer 4 and are optimized for extreme performance, ultra-low latency, and handling sudden traffic spikes. According to AWS Certified Security – Specialty documentation, using a TCP listener on an NLB allows TLS traffic to pass through directly to backend containers without termination, preserving true end-to-end encryption.

This approach eliminates the overhead of decrypting and re-encrypting traffic at the load balancer, reducing latency and maximizing throughput. NLBs scale automatically to handle volatile traffic patterns and millions of requests per second.

Application Load Balancers operate at Layer 7 and introduce additional latency due to TLS termination and HTTP processing. Route 53 multivalue routing does not provide load balancing at the transport layer and does not ensure encryption handling.

AWS recommends NLB TCP pass-through for high-performance, end-to-end encrypted container workloads.

Referenced AWS Specialty Documents:

AWS Certified Security – Specialty Official Study Guide

Elastic Load Balancing Architecture

Network Load Balancer Performance Characteristics

AWS KMS enforces a mandatory minimum waiting period of 7 days before a customer managed key can be deleted. According to AWS Certified Security – Specialty incident response guidance, no method exists to immediately delete a KMS key. The fastest possible deletion is achieved by scheduling deletion with the minimum 7-day waiting period.

In this scenario, although deletion was previously scheduled, the key remains enabled and usable. The most authoritative and reliable method to regain control and reissue deletion immediately is to use the AWS account root user, which has implicit permissions to manage KMS keys regardless of compromised IAM principals.

Option B is incorrect because KMS keys are regional resources; multi-Region keys require coordinated deletion but do not shorten the waiting period. Option C is unnecessary because the key policy already allows kms:*. Option D increases the deletion waiting period to 30 days, which violates the requirement to delete the key as quickly as possible.

AWS documentation clearly states that root user access is the ultimate authority for KMS key management and that 7 days is the minimum deletion window, making this the fastest valid option.

AWS Certified Security – Specialty Official Study Guide

AWS Key Management Service Developer Guide

AWS Incident Response Best Practices