Detect and Notify on Network ACL (NACL) Changes

AWSTemplateFormatVersion: '2010-09-09'
Description: ''
Resources:
  EventRule:
    Type: 'AWS::Events::Rule'
    Properties:
      Name: detect-network-acl-changes
      Description: >-
        A CloudWatch Event Rule that detects changes to network ACLs and
        publishes change events to an SNS topic for notification.
      State: ENABLED
      Targets:
        - Arn:
            Ref: SnsTopic
          Id: target-id1
      EventPattern:
        detail-type:
          - AWS API Call via CloudTrail
        detail:
          eventSource:
            - ec2.amazonaws.com
          eventName:
            - CreateNetworkAcl
            - CreateNetworkAclEntry
            - DeleteNetworkAcl
            - DeleteNetworkAclEntry
            - ReplaceNetworkAclEntry
            - ReplaceNetworkAclAssociation
  SnsTopic:
    Type: 'AWS::SNS::Topic'
    Properties:
      Subscription:
        - Endpoint: email@example.com
          Protocol: email
      TopicName: event-rule-action
  SnsTopicPolicy:
    Type: 'AWS::SNS::TopicPolicy'
    Properties:
      PolicyDocument:
        Statement:
          - Sid: __default_statement_ID
            Effect: Allow
            Principal:
              AWS: '*'
            Action:
              - 'SNS:GetTopicAttributes'
              - 'SNS:SetTopicAttributes'
              - 'SNS:AddPermission'
              - 'SNS:RemovePermission'
              - 'SNS:DeleteTopic'
              - 'SNS:Subscribe'
              - 'SNS:ListSubscriptionsByTopic'
              - 'SNS:Publish'
              - 'SNS:Receive'
            Resource:
              Ref: SnsTopic
            Condition:
              StringEquals:
                'AWS:SourceOwner':
                  Ref: 'AWS::AccountId'
          - Sid: TrustCWEToPublishEventsToMyTopic
            Effect: Allow
            Principal:
              Service: events.amazonaws.com
            Action: 'sns:Publish'
            Resource:
              Ref: SnsTopic
      Topics:
        - Ref: SnsTopic
Parameters: {}
Metadata: {}
Conditions: {}