4.14 Ensure a log metric filter and alarm exist for VPC changes - 'subscription exists'

Warning! Audit Deprecated

This audit has been deprecated and will be removed in a future update.

Information

Real-time monitoring of API calls can be achieved by directing CloudTrail Logs to CloudWatch Logs and establishing corresponding metric filters and alarms. It is possible to have more than 1 VPC within an account, in addition it is also possible to create a peer connection between 2 VPCs enabling network traffic to route between VPCs. It is recommended that a metric filter and alarm be established for changes made to VPCs.

Rationale:

Monitoring changes to VPC will help ensure VPC traffic flow is not getting impacted.

Solution

Perform the following to setup the metric filter, alarm, SNS topic, and subscription:

Create a metric filter based on filter pattern provided which checks for VPC changes and the <cloudtrail_log_group_name> taken from audit step 1.

aws logs put-metric-filter --log-group-name <cloudtrail_log_group_name> --filter-name '<vpc_changes_metric>' --metric-transformations metricName= '<vpc_changes_metric>' ,metricNamespace='CISBenchmark',metricValue=1 --filter-pattern '{ ($.eventName = CreateVpc) || ($.eventName = DeleteVpc) || ($.eventName = ModifyVpcAttribute) || ($.eventName = AcceptVpcPeeringConnection) || ($.eventName = CreateVpcPeeringConnection) || ($.eventName = DeleteVpcPeeringConnection) || ($.eventName = RejectVpcPeeringConnection) || ($.eventName = AttachClassicLinkVpc) || ($.eventName = DetachClassicLinkVpc) || ($.eventName = DisableVpcClassicLink) || ($.eventName = EnableVpcClassicLink) }'

Note: You can choose your own metricName and metricNamespace strings. Using the same metricNamespace for all Foundations Benchmark metrics will group them together.

Create an SNS topic that the alarm will notify

aws sns create-topic --name <sns_topic_name>

Note: you can execute this command once and then re-use the same topic for all monitoring alarms.

Create an SNS subscription to the topic created in step 2

aws sns subscribe --topic-arn <sns_topic_arn> --protocol <protocol_for_sns> --notification-endpoint <sns_subscription_endpoints>

Note: you can execute this command once and then re-use the SNS subscription for all monitoring alarms.

Create an alarm that is associated with the CloudWatch Logs Metric Filter created in step 1 and an SNS topic created in step 2

aws cloudwatch put-metric-alarm --alarm-name '<vpc_changes_alarm>' --metric-name '<vpc_changes_metric>' --statistic Sum --period 300 --threshold 1 --comparison-operator GreaterThanOrEqualToThreshold --evaluation-periods 1 --namespace 'CISBenchmark' --alarm-actions <sns_topic_arn>

Item Details

Audit Name: CIS Amazon Web Services Foundations L1 1.3.0

Category: AUDIT AND ACCOUNTABILITY

Plugin: amazon_aws

Control ID: 270d6c31c09949ee5fd759c7dbacfc4431cca99eb63641fe992cb01a0df47886

Detections

Analytics

4.14 Ensure a log metric filter and alarm exist for VPC changes - 'subscription exists'

Warning! Audit Deprecated

Information

Solution

See Also

Item Details