This sample project demonstrates how to use Amazon EventBridge and AWS Lambda to respond to AWS CloudTrail events. In this example, any AdvertiseByoipCidr call triggers a Lambda function to run and validate whether or not the address space is expected to be advertised by checking for the address space in a list of allowed CIDRs in a DynamoDB table.

If the address space is not permitted to be advertised, the Lambda will publish a message to a SNS Topic to notify an administrator that an unexpected CIDR was advertised and will automatically remove the advertisement of the CIDR.

This pattern deploys an EventBridge rule, a Lambda function, a DynamoDB table and a SNS topic.