Wireless sensor networks have become so widespread where they have become an important part of our daily lives. Wireless sensor networks have characteristics that distinguish them from other communication systems. However, these networks suffer from security gaps and threats such as presence of malicious nodes. The main objective of this work is detecting the presence of such nodes in sensor networks. Detecting malicious nodes helps in reducing power consumption, delay, and packet drop rate. This in turn reflects positively on the performance of these networks. Throughput, power consumption, and delay have been studied for the purpose of detecting the presence of the malicious node in a sensor network. Empirical study has been performed in this work using NS-2 simulator.