Description

Real-time monitoring of API calls can be achieved by directing CloudTrail logs to CloudWatch logs and establishing corresponding metric filters and alarms. Security Groups are a stateful packet filter controlling ingress and egress traffic within a VPC. It is recommended to set up a metric filter and alarm for detecting changes to security groups to ensure resources and services are not unintentionally exposed.

Remediation

For instructions on setting up CloudWatch metric filters and alarms for security group changes, refer to the AWS CloudWatch Alarms for CloudTrail User Guide.

aws logs put-metric-filter --log-group-name <cloudtrail_log_group_name> \
--filter-name <security_group_changes_metric> --metric-transformations \
metricName=<security_group_changes_metric>,metricNamespace="CISBenchmark",metricValue=1 \
--filter-pattern '{($.eventName = AuthorizeSecurityGroupIngress) || ($.eventName = AuthorizeSecurityGroupEgress) || \
($.eventName = RevokeSecurityGroupIngress) || ($.eventName = RevokeSecurityGroupEgress) || ($.eventName = CreateSecurityGroup) || \
($.eventName = DeleteSecurityGroup) }'

You can choose your own metricName and metricNamespace strings. Use the same metricNamespace for all Foundations Benchmark metrics to group them together.