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How to Find AWS API Gateways Without SSL Client Authentication

Man-in-the-middle attacks are possible and other similar risks.

info

This security check is part of the CIS Amazon Web Services Benchmarks and is rated severity medium.

Prerequisites​

This guide assumes that you have already installed and configured Fix Inventory to collect your AWS resources.

Directions​

  1. Execute the following search command in Fix Inventory Shell:

    > search is(aws_apigateway_stage) and stage_client_certificate_id==null <-[2]- is(aws_apigateway_rest_api)
    ​kind=aws_apigateway_stage, ..., region=fixinventory-poweruser
    ​kind=aws_apigateway_stage, ..., account=poweruser-team

  2. Pipe the search command into the dump command:

    > search is(aws_apigateway_stage) and stage_client_certificate_id==null <-[2]- is(aws_apigateway_rest_api) | dump
    ​reported:
    ​  id: /aws/apigateway/123
    ​  name: some-name
    ​  ctime: '2022-12-05T22:53:14Z'
    ​  kind: aws_apigateway_stage
    ​  age: 2mo28d

    The command output will list the details of all non-compliant aws_apigateway_stage resources.

Remediation​

Enable client certificate. Mutual TLS is recommended and commonly used for business-to-business (B2B) applications. It is used in standards such as Open Banking. API Gateway now provides integrated mutual TLS authentication at no additional cost.

note

Please refer to the AWS API Gateway documentation for details.

Further Reading​