Action Dispatch HostAuthorization

This middleware guards from DNS rebinding attacks by explicitly permitting the hosts a request can be sent to, and is passed the options set in config.host_authorization.

Requests can opt-out of Host Authorization with exclude:

config.host_authorization = { exclude: ->(request) { request.path =~ /healthcheck/ } }

When a request comes to an unauthorized host, the response_app application will be executed and rendered. If no response_app is given, a default one will run. The default response app logs blocked host info with level ‘error’ and responds with 403 Forbidden. The body of the response contains debug info if config.consider_all_requests_local is set to true, otherwise the body is empty.