Real-time monitoring of API calls can be achieved by directing CloudTrail Logs to CloudWatch Logs and establishing corresponding metric filters and alarms. Network gateways are required to send/receive traffic to a destination outside of a VPC. Monitoring changes to network gateways will help ensure that all ingress/egress traffic traverses the VPC border via a controlled path.
Recommended Mitigation
It is recommended that a metric filter and alarm be established for changes to network gateways.
Logging and monitoring
