CloudWatch log metric filter and alarm for VPC security group changes should be configured

Description

It is recommended that users establish a metric filter and alarm for changes to Security Groups. Monitoring changes to security groups helps to ensure that resources and services are not unintentionally exposed.

Console Remediation Steps

This is a two part process. First, you create a Metric Filter for specific CloudTrail log events. Next, you create a CloudWatch alarm for the filter. See Creating CloudWatch Alarms for CloudTrail Events: Examples for more information.

  • Step 1: To create the Metric Filter:

    • Navigate to CloudWatch.

    • In the left navigation, click Log Groups and select the desired log group. The log group must be assigned to a multi-region CloudTrail trail that has logging enabled (i.e., is in Logging status).

    • Select Metric filters > Create Metric Filter.

    • In Filter pattern, enter the following: { ($.eventName = AuthorizeSecurityGroupIngress) || ($.eventName = AuthorizeSecurityGroupEgress) || ($.eventName = RevokeSecurityGroupIngress) || ($.eventName = RevokeSecurityGroupEgress) || ($.eventName = CreateSecurityGroup) || ($.eventName = DeleteSecurityGroup) }

    • Click Next.

    • For Filter name, type SecurityGroupEvents.

    • For Metric namespace, type CloudTrailMetrics.

    • For Metric name, type SecurityGroupEventCount.

    • For Metric value, type 1.

    • Click Next > Create metric filter.

  • Step 2: To create an Alarm:

    • Check the box next to the newly created metric filter and click Create alarm.

    • Select the Threshold type.

    • Define the alarm condition and threshold value.

    • Click Next.

    • In Alarm state trigger, select In alarm.

    • Select an existing SNS topic, create new topic, or use topic ARN. Note that the SNS topic must have at least one subscriber.

      • If you selected to create a new topic, enter a name in Create a new topic.

      • Enter an email address in Email endpoints that will receive the notification.

      • Click Create topic.

    • Click Next.

    • Enter an Alarm name.

    • Optionally, enter an alarm description.

    • Click Next > Create alarm.

CLI Remediation Steps