Metadata

Id: cloudformation-aws-api-gateway-with-open-access

Provider: AWS

Platform: CloudFormation

Severity: Medium

Category: Insecure Configurations

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• Provider Reference

Description

API Gateway methods must not set AuthorizationType to NONE except for CORS preflight (OPTIONS) requests, because leaving a method unauthenticated allows anyone to invoke the endpoint and can lead to unauthorized access, data exposure, or backend abuse.

For AWS::ApiGateway::Method resources, AuthorizationType must specify an authentication mechanism (for example, AWS_IAM, CUSTOM, or COGNITO_USER_POOLS) when HttpMethod is not OPTIONS. This rule flags Resources.<name>.Properties where AuthorizationType is NONE and HttpMethod is not OPTIONS.

If you use CUSTOM, also set AuthorizerId to reference a configured authorizer. If you use COGNITO_USER_POOLS or AWS_IAM, ensure the corresponding user pool or IAM policies and roles are correctly configured.

Secure configuration example (CloudFormation YAML):

MyMethod:
  Type: AWS::ApiGateway::Method
  Properties:
    HttpMethod: POST
    AuthorizationType: AWS_IAM
    RestApiId: !Ref MyApi
    ResourceId: !Ref MyResource
    Integration:
      Type: AWS_PROXY
      IntegrationHttpMethod: POST
      Uri: !Sub arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${MyFunction.Arn}/invocations

Compliant Code Examples

AWSTemplateFormatVersion: "2010-09-09"
Description: "Router53"
Resources:
  MockMethod:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      RestApiId: !Ref MyApi
      ResourceId: !GetAtt
        - MyApi
        - RootResourceId
      HttpMethod: OPTIONS
      AuthorizationType: NONE
      Integration:
        Type: MOCK

Non-Compliant Code Examples

AWSTemplateFormatVersion: "2010-09-09"
Description: "Router53"
Resources:
  MockMethod:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      RestApiId: !Ref MyApi
      ResourceId: !GetAtt
        - MyApi
        - RootResourceId
      HttpMethod: GET
      AuthorizationType: NONE
      Integration:
        Type: MOCK