The EC2 VPC Modified detection rule is designed to monitor changes made to Amazon EC2 Virtual Private Clouds (VPCs) through AWS CloudTrail logs. When a VPC is modified, the event is logged and triggers an alert if the modification is considered anomalous or outside of the expected operational parameters. This monitoring method leverages the detailed logging capabilities of AWS CloudTrail, tracking various attributes including event names, user agents, source IP addresses, and AWS resource ARNs. Given the criticality of VPC settings in maintaining secure and efficient networking environments, this rule aims to ensure that any unauthorized or unintended modifications are promptly identified and reported. The rule checks for specific event names like `CreateVpc`, signaling the addition of a new VPC, and captures additional context such as user identity and IP address to assess the legitimacy of the modification. Alerts generated by this rule are categorized under the severity level of 'Info'. For further investigation, a detailed runbook is provided to suggest steps for response and remediation.