Exposure of WSDL File Containing Sensitive Information

Description

This vulnerability occurs when a Web Service Definition Language (WSDL) file, which acts as a public blueprint for a web service, is exposed in a way that reveals sensitive information about the application's internal structure or functionality.

Extended Description

A WSDL file is automatically generated to tell clients how to interact with a web service, detailing available methods, required parameters, and data types. The security risk arises when this technical specification is made accessible to a broader audience than intended, such as being publicly reachable on the internet instead of restricted to trusted developers or systems. This overexposure can provide attackers with a detailed map of your application's entry points. Specifically, the file often lists all service methods, including those that are internal, administrative, or deprecated and should not be publicly called. Attackers can use this information to discover hidden functionality, guess the names or locations of unprotected resources, and craft precise attacks against the backend logic. The problem is frequently compounded because WSDL generation is an automated process that may pull details directly from the code without security filtering.

Common Consequences 1

Scope: Confidentiality

Impact: Read Application Data

The attacker may find sensitive information located in the WSDL file.

Potential Mitigations 3

Phase: Architecture and Design

Limit access to the WSDL file as much as possible. If services are provided only to a limited number of entities, it may be better to provide WSDL privately to each of these entities than to publish WSDL publicly.

Phase: Architecture and Design

Strategy: Separation of Privilege

Make sure that WSDL does not describe methods that should not be publicly accessible. Make sure to protect service methods that should not be publicly accessible with access controls.

Phase: Architecture and Design

Do not use method names in WSDL that might help an adversary guess names of private methods/resources used by the service.

Demonstrative Examples 1

The WSDL for a service providing information on the best price of a certain item exposes the following method: float getBestPrice(String ItemID) An attacker might guess that there is a method setBestPrice (String ItemID, float Price) that is available and invoke that method to try and change the best price of a given item to their advantage. The attack may succeed if the attacker correctly guesses the name of the method, the method does not have proper access controls around it and the service itself has the functionality to update the best price of the item.