The latest version of ZigBee offers improvements over many aspects like low power consumption, flexibility and inexpensive deployment. However problems persist, as the enhanced protocol still has many security weaknesses due to the fact that constrained wireless sensor network devises cannot uses standard security protocols such as public key cryptography mechanisms. In this paper, we highlight relevant security concerns related to ZigBee security features, then we propose a new approach suitable for ZigBee enabled wireless sensor networks. The proposed solution decreases considerably the likelihood of successful attacks,and reduces security impact in the event of a node compromise. Lastly we discuss the security and performance related to the proposed scheme.