GCP-NET - VPC Flow - High Egress Volume to External IP
This rule detects high-volume outbound network traffic from a Google Cloud Platform (GCP) source IP to external (non-private/non-internal) destinations. It establishes a baseline of daily outbound traffic per source IP over time and triggers an alert if the current daily outbound volume exceeds 500MB and shows a significant increase (more than 3x the established average) compared to previous days. This behavior is often indicative of unauthorized data exfiltration or abnormal network activity.
Sigma
