Weakness Found in Wi-Fi Security Protocol
November 06, 2003
A glaring weakness in the interface design of the WPA protocol could open the door to passphrase cracking attacks.
A wireless security expert has detected a glaring weakness in the
interface design of a highly touted Wi-Fi Protected Access (WPA) protocol
deployed in numerous Wireless LAN
According to a research paper posted on Wi-Fi Networking News, the weakness could allow intruders to crack poorly chosen passphrases via offline dictionary attacks.
The weakness detailed in the research paper written by IEEE and IETF
committee member Robert Moskowitz means that Wi-Fi
The WPA standard, unveiled in
late 2002 as the replacement for WEP
The TKIP feature scrambles the keys using a hashing algorithm and, by adding an integrity-checking feature, ensures that the keys haven't been tampered with. WEP, on the other hand, uses a static key that is seldom changed by users. This cryptographic weakness is responsible for many of the known security issues in WLANs because intruders could easily figure out an encryption key and access a wireless network.
The latest weakness only takes effect when short, text-based keys are
used and does not reflect a fault in the WPA
And, according to Moskowitz, the weakness can be avoided if WLAN hardware manufacturers build units with the ability to generate random keys that can be copied and pasted across systems. Manufacturers can also restrict the ability to enter weak keys by requiring passphrases with numerous characters instead of words that can be found in the dictionary.
The researcher warned that dictionary based programs used to crack passwords are heavily used by criminal hackers.
has rolled out a free Windows
XP download with support for WPA.
The XP update tweaks the way the OS communicates with the Wi-Fi protocol.
Instead of having one encrypted key for everyone to connect to the network,
Microsoft said its WPA update would provide separate keys for each system
connecting to the Wi-Fi network.