Detect Spike in Blocked Outbound Traffic from AWS VPC

The analytic identifies spikes in blocked outbound network connections originating from within an AWS environment. It uses VPC Flow Logs data from CloudWatch, specifically looking for 'blocked' actions from internal IP ranges (10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16) to external destinations. A spike is determined by comparing the current number of blocked connections against a calculated baseline (average and standard deviation) over time. This detection is significant as it can indicate potential exfiltration attempts or misconfigurations leading to data leakage. If confirmed malicious, such activity could allow attackers to bypass network defenses, leading to unauthorized data transfer or communication with malicious external entities.