Ensuring security of systems based on supervisory control and data acquisition is a major challenge. The goal of this paper is to develop the model-based techniques capable of detecting integrity attacks on the sensors of a control system. In this paper, the effect of integrity attacks on the control systems is analyzed and countermeasures capable of exposing such attacks are proposed. The main contributions of this paper, beyond the novelty of the problem formulation, lies in enumerating the conditions of the feasibility of the replay attack, and suggesting countermeasures that optimize the probability of detection by conceding control performance. The methodologies are shown and the theoretical results are validated using several sets of simulations.