With the colossal growth of wireless sensor networks (WSNs) in different applications starting from home automation to military affairs, the pressure on ensuring security in such a network is paramount. Considering the security challenges, it is really a hard-hitting effort to develop a secured WSN system. Moreover, as the information technology is getting popular, the intruders are also planning new ideas to break the system security, to harm the network and to make the system quality down with the target of taking the control of the network to corrupt it or to get benefits from it anyway. The intruders corrupt the system only when the security breaking cost (SBC) is lower compared with the benefits they attained or the harm it can make to others. In this paper, the authors define the term “maximizing network interruption problem” and propose a technique, called the grid point approximation algorithm, to estimate the SBC of a multi-hop WSN so that it can be made tougher for an intruder to break the system security. It is assumed that the intruder has the complete picture of the entire network. The technique is designed from the intruder’s point of view for completely jamming all the sensor nodes in the network through placing jammers or malicious nodes strategically and at the same time keeping the number of jammer nodes to minimum or near minimum. To the best of the authors’ knowledge, there is no work proposed so far of the same kind. Experimental results with the changes of the different network parameters show that the proposed algorithm is able to provide excellent performances to achieve the targets.