Wireless Sensor Networks (WSNs) are vastly used networks that have caught attention of numerous researchers because of their various applications. They are resource constrained networks where memory capacity, energy and consumption of memory are limited. Therefore they are susceptible to several security threats and attacks. One such attack is Distributed Denial of Service (DDoS). These attacks' objective is to overwhelm the target with ample packets so that its resources get drained and also thwart its ability to procure genuine packets so that the victim fails to give desired response. This leads to the congestion of the network and the victim becomes exhausted leading to denial of service. In this paper we propose a traffic filtration mechanism which deploys mitigation measures to restrain the attackers' attempt at deluging the wireless sensor network with the motive of causing denial of service with enormous packets within limited time.