The rule titled 'AWS EC2 Route Table Modified or Deleted' is designed to identify unauthorized changes to AWS EC2 route tables via AWS CloudTrail events. The rule triggers on actions such as `ReplaceRoute`, `ReplaceRouteTableAssociation`, `DeleteRouteTable`, `DeleteRoute`, or `DisassociateRouteTable`, which may represent legitimate administrative activities or malicious attempts to disrupt network traffic, reroute communications, or maintain persistence within a compromised environment. It inspects AWS CloudTrail logs for these specific actions that occurred in the last 10 days, using the field `aws.cloudtrail.user_identity.arn` to identify the user or role responsible for the action. The rule aims to prevent potential service disruptions and unauthorized access by monitoring these critical changes in real-time, allowing for swift investigations and response actions. Investigative steps include reviewing request parameters, validating user context, analyzing request details, and correlating related activities. This proactive approach helps in identifying adversarial behavior while acknowledging and managing the possibility of false positives due to routine administrative and automation processes. The risk score is classified as low, suggesting that although changes can indicate malicious activities, they often align with standard operational practices in the AWS environment.