Security in low rate wireless personal area network (LR-WPAN) is a challenging task in wireless network. Wireless communications are inherently susceptible to interception and interference. Most devices in LR-WPAN are resource-constrained and lack physical safeguards. Detection mechanism against distributed denial of service (DDoS) attacks is a critical component of any security system in which these attacks can affect the availability of a node or an entire network. In this work, we focus the detection mechanism against DDoS attacks in IEEE 802.15.4 using fuzzy logic system. It is an attack detection mechanism which uses an anomaly-based approach and operates in a distributed manner and distinguishes attack scenarios from the impact of traffic load on network behaviour. By stimulation results, we finalised potential areas in DDoS attacks and provide evidence of effectiveness for detection of DDoS attacks with improved detection rate.