Wildcard In ACM Certificate Domain Name

• Query id: cc8b294f-006f-4f8f-b5bb-0a9140c33131
• Query name: Wildcard In ACM Certificate Domain Name
• Platform: CloudFormation
• Severity: Low
• Category: Insecure Configurations
• URL: Github

Description

ACM Certificate should not use wildcards (*) in the domain name
Documentation

Code samples

Code samples with security vulnerabilities

Positive test num. 1 - yaml file

AWSTemplateFormatVersion: '2010-09-09'
Parameters:
  DomainName:
    Description: "Domain for which you are requesting a cert"
    Type: String
    Default: example.com #Put your own domain name here
  HostedZoneId:
    Description: "hosted zone id in which CNAME record for the validation needs to be added"
    Type: String
    Default: XYZABCDERYH #Put the hosted zone id in which CNAME record for the validation needs to be added

Resources:
  Certificate:
    Type: AWS::CertificateManager::Certificate
    Properties:
      DomainName: "*"
      DomainValidationOptions:
        - DomainName: !Ref DomainName
          HostedZoneId: !Ref HostedZoneId
      ValidationMethod: 'DNS'

Positive test num. 2 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Parameters": {
    "HostedZoneId": {
      "Type": "String",
      "Default": "XYZABCDERYH",
      "Description": "hosted zone id in which CNAME record for the validation needs to be added"
    },
    "DomainName": {
      "Description": "Domain for which you are requesting a cert",
      "Type": "String",
      "Default": "example.com"
    }
  },
  "Resources": {
    "Certificate": {
      "Type": "AWS::CertificateManager::Certificate",
      "Properties": {
        "DomainName": "*",
        "DomainValidationOptions": [
          {
            "DomainName": "DomainName",
            "HostedZoneId": "HostedZoneId"
          }
        ],
        "ValidationMethod": "DNS"
      }
    }
  }
}

Code samples without security vulnerabilities

Negative test num. 1 - yaml file

AWSTemplateFormatVersion: '2010-09-09'
Parameters:
  DomainName:
    Description: "Domain for which you are requesting a cert"
    Type: String
    Default: example.com #Put your own domain name here
  HostedZoneId:
    Description: "hosted zone id in which CNAME record for the validation needs to be added"
    Type: String
    Default: XYZABCDERYH #Put the hosted zone id in which CNAME record for the validation needs to be added

Resources:
  Certificate:
    Type: AWS::CertificateManager::Certificate
    Properties:
      DomainName: CMDomain
      DomainValidationOptions:
        - DomainName: !Ref DomainName
          HostedZoneId: !Ref HostedZoneId
      ValidationMethod: 'DNS'

Negative test num. 2 - json file

{
  "AWSTemplateFormatVersion": "2010-09-09",
  "Parameters": {
    "DomainName": {
      "Type": "String",
      "Default": "example.com",
      "Description": "Domain for which you are requesting a cert"
    },
    "HostedZoneId": {
      "Description": "hosted zone id in which CNAME record for the validation needs to be added",
      "Type": "String",
      "Default": "XYZABCDERYH"
    }
  },
  "Resources": {
    "Certificate": {
      "Type": "AWS::CertificateManager::Certificate",
      "Properties": {
        "DomainName": "CMDomain",
        "DomainValidationOptions": [
          {
            "HostedZoneId": "HostedZoneId",
            "DomainName": "DomainName"
          }
        ],
        "ValidationMethod": "DNS"
      }
    }
  }
}