For distributed software systems, ensuring their availability under intentional attacks is critical. Traffic analysis, conducted by the attacker, could reveal the protocol being carried out by the components.Furthermore, having inferred the protocol, the attacker can use the pattern of the messages as a guide to the most critical components. We thwart these directed attacks by using message forwarding to reduce traffic differences, thus diverge attackers from targeted attack to random attack, which probabilistically prolongs the availability of important components in the system. The simulation results also show that message forwarding effectively balance the traffic flow and hence indicate the validity of our approach.