A Client Puzzle Based Defense Mechanism to Resist DoS Attacks in WLAN

Wireless networking technologies based on the IEEE802.11 series of standards fail to authenticate management frames and network card addresses and suffer from serious vulnerabilities that may lead to denial of service attacks, this paper proposes a client puzzle based defense mechanism to resist two resource depletion type DoS attacks: authentication and association attacks, in the proposed mechanism, we ask the client to solve a puzzle send by the access point, this puzzle could only be solved by brute force. The difficulty degree of the puzzle could be easily adjusted by access point. In our mechanism, parameters are placed into unused field of the management frames. The effectiveness of our mechanism in defending DoS attacks is demonstrated using our experimental results.