Interaction faults caused by a flawed external system designed by a third party are a major issue faced by interconnected systems. Fault injection is a valuable tool for evaluating the dependability of such scenarios. Several types of errors caused by interaction faults may be injected by existing approaches, even though previous work focused on other types of faults, such as hardware and software faults. This is not the case of inconsistent values -data that is correctly received and syntactically correct, but inconsistent with what it should represent. In this paper, we propose a novel methodology to inject inconsistent values caused by interaction faults, including hand-defined, random and semantically significant values. We also describe a simulation tool which implements the proposed mechanism to aid dependability evaluation in a system that uses the Universal Plug and Play standard to communicate.