Ensure a log metric filter and alarm exist for changes to Network Access Control Lists (NACL)

Property
Language
Severity
Service	cloudwatch
Provider	AWS

Description#

You can do real-time monitoring of API calls by directing CloudTrail logs to CloudWatch Logs and establishing corresponding metric filters and alarms.
NACLs are used as a stateless packet filter to control ingress and egress traffic for subnets in a VPC.

CIS recommends that you create a metric filter and alarm for changes to NACLs. Monitoring these changes helps ensure that AWS resources and services aren’t unintentionally exposed.

Resolution#

Create an alarm to alert on network acl changes