The Web services architecture may require exposing a WSDL file that contains information on the publicly accessible services and how callers of these services should interact with them (e.g. what parameters they expect and what types they return).
Extended Description
An information exposure may occur if any of the following apply:
The WSDL file is accessible to a wider audience than intended.
The WSDL file contains information on the methods/services that should not be publicly accessible or information about deprecated methods. This problem is made more likely due to the WSDL often being automatically generated from the code.
Information in the WSDL file helps guess names/locations of methods/resources that should not be publicly accessible.
Time of Introduction
Architecture and Design
Implementation
Operation
Applicable Platforms
Languages
All
Technology Classes
Web-Server: (Often)
Common Consequences
Scope
Effect
Confidentiality
Technical Impact: Read application
data
The attacker may find sensitive information located in the WSDL
file.
Enabling Factors for Exploitation
The system employs a web services architecture.
WSDL is used to advertise information information on how to communicate
with the service.
Observed Examples
Reference
Description
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.
Potential Mitigations
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.
Description
