org-master-cf-template.yaml

AWSTemplateFormatVersion: '2010-09-09'
Description: 'Role in AWS organizations master account'
Parameters:
  OrgListAccountsViewerRoleName:
    Type: String
    Default: "OrgListAccountsViewer"
  CentralAggregatorAwsAccountId:
    Type: Number
    Description: "Account Id of the central aggregator AWS account."
  SupportAggregatorRoleName:
    Type: String
    Description: "Required role in central aggregator account."
    Default: "SupportAggregator"

Resources:
  OrgListAccountsViewer:
    Type: AWS::IAM::Role
    # Role assumed from support cases central aggregator account to get list of accounts
    Properties:
      RoleName: !Ref OrgListAccountsViewerRoleName
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Sid: TrustSupportAggregator
            Effect: Allow
            Principal:
              AWS: !Sub "arn:aws:iam::${CentralAggregatorAwsAccountId}:role/${SupportAggregatorRoleName}"
            Action:
              - sts:AssumeRole
      Path: "/"
      Policies:
        - PolicyName: "list-org-accounts"
          PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Effect: "Allow"
                Action:
                  - "organizations:ListAccounts"
                Resource: "*"