In this paper, the authors formulate an analytical model to characterize the spread of malware in mobile networks and to deploying an efficient defense system to protect and helps infected nodes. Using a compartmental model, they derive the system parameters or network conditions under which the mobile networks may reach a malware free equilibrium. Here they analyze in that mobile network how to distribute the signatures that is based on content. Which helps to detect the corresponding malware and disable further propagation used to minimize the infected nodes, here they propose the encounter based distributed algorithm to achieve optimal solution.