Dictionary attack against Cisco's LEAP, Wireless LANs vulnerable

[Michael Renzmann <security@dylanic.de>]

Hi.

Cisco released a security notice [1] in August about possible dictionary 
attacks against their proprietary LEAP (Lightweight Extensible 
Authentication Protocol, used with 802.1x). But according to 
Computerworld [2] it seems that this information has not been spread 
well enough.

In addition, Unstrung yesterday reported [3] about the demonstration of 
a tool that seems to be able to retrieve valid passwords for LEAP 
protected WLANs within "minutes, even seconds". The tool is not 
available yet, but its author (Joshua Wright from Johnson & Wales 
University) announced "that the tool will be generally available in a 
couple of months".

Those of you who are using LEAP to protect their Wireless LAN should 
take care of a proper password policy and change passwords regularly. 
Cisco provides further information on password selection in their 
advisory ("Available Documentation", last paragraph).

Bye, Mike

[1] 
http://www.cisco.com/en/US/tech/tk722/tk809/technologies_tech_note09186a00801aa80f.shtml
[2] 
http://www.computerworld.com/mobiletopics/mobile/story/0,10801,85637,00.html?f=x68
[3] http://www.unstrung.com/document.asp?doc_id=41185