Formal Verification of IEEE 802.11 Authentication Protocols

IEEE 802.11 is the standard designed to provide secured communication in wireless LAN. The IEEE 802.11i specification contains both WPA-PSK, WPA-GPG authentication protocols. IEEE 802.11w authentication protocol enhances the IEEE802.11i security for selected management frames. These protocols allow a wireless station to gain access to a protected wireless network managed by an access point. In this paper, a section of the protocols is chosen for modeling and verification. Communicating Sequential Process (CSP) is used for modeling and the verification is performed using CasperFDR. It can perform an exhaustive verification that can establish with mathematical certainty whether or not a given behavior is error-free and used to specify a system behavior in a formal validation model that defines interactions between the processes. We have analyzed and verified secrecy and authentication properties of the WPAPSK, WPA-GPG and IEEE802.11w authentication protocols. This paper models both IEEE802.11i and IEEE802.11w authentication protocols by formal verification and analyzes the output. A few attacks are found in these protocols. The specifications through which these attacks were found are presented. The IEEE 802.11w authentication protocol is also modified in such a way that it is strong against to the attacks performed by intruder.