In this paper, the authors introduce a new attack, Reinforcement Swap Attack, against Directed Diffusion based WSNs, which exploits the vulnerabilities of Directed Diffusion specifications. Its main idea is the disruption of configuration information, such as routing information to misuse route establishment along the network. Their approach is to swap Directed Diffusion reinforcement rule which means that the good route is excluded and the bad route is included. Moreover, their attack is activated and deactivated periodically to prolong its lifetime and hence brings down the target network. For the proposed attack, they present analysis, simulation, and experimental measurements.