Research On WLAN Attack Technology

Wireless LAN has the mobility and flexibility, which cannot be provided by the traditional wired network. As a result, wireless LAN has gained much popularity. But with the added convenience of wireless access come new problems, not the least of which are heightened security concerns. When transmissions are broadcast over radio waves, interception and masquerading become trivial to anyone with a radio, and so there is a need to employ security mechanisms to protect the communications.The 802.11 standard for wireless LAN communications introduces the Wired Equivalent Privacy protocol, used to protect link-layer communications, in an attempt to bring the security level of wireless systems closer to that of wired ones. The primary goal of WEP is to protect the confidentiality of user data from eavesdropping and other attacks.Through analysis of WEP, several serious security flaws are discovered in the protocol, which shows that WEP fails to attain its security goals. Exploiting these flaws,some approaches are proposed to launch attacks against wireless LANs.Based on these attack approaches, an attack tool is designed against 802.11 WLAN. By setting wireless card as RF monitoring mode, this tool can capture packets in WLAN. Then, this tool analyzes and filters the packets captured to acquire relevant information about the network, such as MAC address of AP, SSID and channel. Finally, by computing the data encrypted, the user's encryption key is obtained.The prototype of the WLAN attack tool is implemented under Windows XP with Microsoft Visual C++ 6.0. Theoretical analysis and experiment show that the tool can discover the basic service set being transmitted, and crack the key used to encrypt data in the BSS.