We study the problem of data commercialization in the presence of both legitimate users with heterogeneous demands, as well as adversarial users who purchase data with the aim of compromising its security/privacy. We show that it is never optimal for the data owner to screen for adversarial types. We then characterize the effects of the adversaries' presence on the contract design problem, and contrast this problem's properties with that of the classic monopolistic screening problem. We quantify the effect of adversaries on the data owner's revenue using the notion of ``price of adversary'', and provide bounds on it.