Amazon GuardDuty provides built-in, fully managed threat detection for AWS accounts and workloads, including automatic detection of cryptocurrency mining activity, compromised EC2 instances, command-and-control traffic patterns, and anomalous behaviors. GuardDuty includes multiple threat identifiers such as EC2:CryptoCurrencyActivity.BitcoinToolDetected and EC2:UnauthorizedAccess.CryptoMining. Because this capability is native and requires no custom detection logic, it provides the lowest development and operational overhead compared to alternatives.

When GuardDuty generates a finding, it publishes the event automatically to Amazon EventBridge. The DevOps engineer can create an EventBridge rule that matches the specific mining-related finding types. The target of the rule is an AWS Lambda function that parses instance details from the finding and calls TerminateInstances on the affected EC2 instance.

This enables real-time automated remediation without needing recurring scans, log parsing, or complex data queries.

Options A and B require building custom detection pipelines and maintaining periodic Lambda polling, increasing long-term complexity. Option D (Security Hub) aggregates findings but still relies on GuardDuty for detection, adding unnecessary overhead.

Therefore, GuardDuty + EventBridge + Lambda termination is the easiest, quickest, and most AWS-recommended solution following incident-response best practices.