Wireless Sensor Networks WSNs are being utilized increasingly nowadays due to their ability to collect data from stationary, moving, reachable or unreachable fields. Progressive developments in WSN techniques add efficiency, reliability and better power management possibility, but they are still vulnerable and sensitive to security threats. The most effective threat to WSN is DOS attacks, which are detectable but in many cases unpreventable yet. An authentication-based defensive approach against DOS attack combined with jamming attack that prevents transferring data between attacked nodes in a cluster and cluster head node is proposed in this study. The proposed method encompasses developing an algorithm with ability to bypass attacked path via alternative safe one under control of cluster head to mitigate the False Node Excluding DOS due to jamming attack. The proposed method has been experimentally tested against similar methods from the literature with arbitrary study cases. Our proposed algorithm shows promising results in mitigating False Node Exclusion DOS (FNEDOS) attack where a full recovery of the attacked node is achieved in case of isolated nodes, and improvement between 36% and 52% is obtained when the attack affects a group of nodes at proximity.