Technical Research Of WLAN Security Assessment On Physical And MAC Layer

In Wireless Local Area Network (WLAN), radio frequency signal is used as amedium to transmit data. WLAN is popular for its simple network architecture andthe advantages of flexible to access. However, due to the defects of its opentransmission medium and network protocol, WLAN is vulnerable to various attackssuch as eavesdropping, signal interference, key crack and middleman attack aimed atphysical layer and MAC layer.In this paper we mainly analyze IEEE802.11g2.4G WLAN physical and MAClayer protocol and IEEE802.11i security authentication protocol. We also study theWLAN physical and MAC layer attacks as well as key crack methods to design aWLAN attack system with functions of scanning, cracking, interfering and pseudo AP.The system can be used to obtain the information of the target wireless network andrecover the keys. It also has the function of active and passive attack based on DOS,which can be used to block the transmission and it can be pretended as the same as thetarget AP.Finally, we assess the security performance. If accumulating more than85,000packets and more than15500IVs, it is easy to crack the WEP key. WPA-PSKencryption with simple password can be cracked in seconds, while more time isneeded for complex password. In terms of signal interference, using active interfering,connection between client and AP would be terminated in several seconds. Whileusing passive interference the throughput will be reduced as low as1.5Mbps. Whenthe normal connect is terminated, disconnected clients would select pseudo APwithout awareness.