Practical Exploitation of RC4 Weaknesses in WEP Environments

From: h1kari (h1kari@dachb0den.com)
Date: 02/26/02 

Date: Tue, 26 Feb 2002 13:05:16 -0800
From: h1kari <h1kari@dachb0den.com>
To: "bugtraq@securityfocus.com" <bugtraq@securityfocus.com>, "pen-test@securityfocus.com" <pen-test@securityfocus.com>, "vuln-dev@securityfocus.com" <vuln-dev@securityfocus.com>, "wireless@sdwug.org" <Wireless@sdwug.org>, <wireless@lists.bawug.org>, <bsd-wireless@lists.bawug.org>

Practical Exploitation of RC4 Weaknesses in WEP Environments

This document will give a brief background on 802.11b based WEP weaknesses
and outline a few additional flaws in rc4 that stem off of the concepts
outlined in "Weaknesses in the Key Scheduling Algorithm of RC4" (FMS) and
"Using the Fluhrer, Mantin, and Shamir Attack to Break WEP" (SIR) and
describes specific methods that will allow you to optimize key recovery.
This document is provided as a conceptual supplement to dweputils, a wep
auditing toolset, which is part of the bsd-airtools package provided by
Dachb0den Labs. The basic goal of the article is to provide technical
details on how to effectively implement the FMS attack so that it works
efficiently with both a small amount of iv collection time as well as
cracking and processing time and to provide details on how other pseudo
random generation algorithm (prga) output bytes reveal key information.

http://www.dachb0den.com/projects/bsd-airtools/wepexp.txt

I'd also like to announce that I've just released bsd-airtools v0.2 which
implements this outlined form of attack and allows you to crack weak keys
with quite fewer collected packets than any wep cracking applications that
are currently available.

http://www.dachb0den.com/projects/bsd-airtools.html

Cheers,
-h1kari

Relevant Pages

  • Re: Is RC4 a good choice?
    ... do you mean the concatenation of the master key K and the IV? ... >got WEP in trouble. ... with RC4 is what gives cause for concern and allows the attack. ... And this brilliant attack used the above factors to do damage. ...
    (sci.crypt)
  • [REVS] Practical Exploitation of RC4 Weaknesses in WEP Environments
    ... Forcing, FMS Attack, First Byte attack, RC4 Attacks) and a possible ... This document will give a brief background on 802.11b based WEP weaknesses ...
    (Securiteam)
  • Practical Exploitation of RC4 Weaknesses in WEP Environments
    ... Practical Exploitation of RC4 Weaknesses in WEP Environments ... details on how to effectively implement the FMS attack so that it works ...
    (Bugtraq)
  • Re: rotor alternative?
    ... your cipher is doing, ... you encrypt the same plaintext twice with the same key, ... Being loosely inspired by RC4 is unreassuring on several grounds. ... WEP with a very limited amount of captured traffic. ...
    (comp.lang.python)
  • Re: Why we need to exclude first 256 bytes of key streem
    ... >WEP". ... I am creating the algorithm same like RC4, ... >we need to exclude first 256 bytes of key streem ... Greg Rose ...
    (sci.crypt)