CAPEC Definitions / CAPEC-36
CAPEC-36: Using Unpublished Interfaces or Functionality
An adversary searches for and invokes interfaces or functionality that the target system designers did not intend to be publicly available. If interfaces fail to authenticate requests, the attacker may be able to invoke functionality they are not authorized for.
Extended Description
Adversaries can also search for undocumented bits on a hardware device, commonly known as "chicken bits". These bits are used to enable/disable certain functionality, but are not published. Adversaries can reverse engineer firmware to identify hidden features and change these bits at runtime to achieve malicious behavior.
Mitigations
Authenticating both services and their discovery, and protecting that authentication mechanism simply fixes the bulk of this problem. Protecting the authentication involves the standard means, including: 1) protecting the channel over which authentication occurs, 2) preventing the theft, forgery, or prediction of authentication credentials or the resultant tokens, or 3) subversion of password reset and the like.
Relationships with other CAPECs
CAPEC-113: Interface Manipulation
Prerequisites
The architecture under attack must publish or otherwise make available services that clients can attach to, either in an unauthenticated fashion, or having obtained an authentication token elsewhere. The service need not be 'discoverable', but in the event it isn't it must have some way of being discovered by an attacker. This might include listening on a well-known port. Ultimately, the likelihood of exploit depends on discoverability of the vulnerable service.
