Bugtraq mailing list archives
Re: Cracking preshared keys
From: Michael Thumann <mthumann () ernw de>
Date: Thu, 24 Apr 2003 20:46:21 +0100
To get the XAUTH based authentication information (that is the part where the RADIUS Server is involved) you must start a man in the middle attack and this MITM attack is only possible when you've already cracked the preconfigured preshared key and when you are in physical position to perform a MITM attack (that's really not too easy).
Hope that helps ;- At 21:10 23.04.03 -0400, Gary Flynn wrote:
Damir Rajnovic wrote:Please note that the same class of attack is possible even if Xauth (Extended Authentication) is used. This is because Xauth is performed after Phase 1 is completed and, for this attack, an adversary needs only a packet from Phase 1. Furthermore, after the pre-shared key has been discovered, an adversary can mount an active MiTM attackon Xauth. The outcome depends on the exact authentication method used in Xauth.May I ask how this applies to "IKE Shared Secret AAA"? If a Radius backend authenticator is used, is the shared key that is vulnerable one preconfigured in the VPN hosts or one based on the Radius password? The reason I ask is that the preconfigured shared key can easily be lengthened but the backend password, if based on end user passwords, is not as easy a solution. :) Thank you. Gary Flynn Security Engineer - James Madison University
ERNW Enno Rey Netzwerke GmbH - Zaehringerstr. 46 - 69115 Heidelberg Tel. +49 6221 480390 - Fax +49 6221 419008 - Mobil +49 173 6745903
Current thread:
- Cracking preshared keys Michael Thumann (Apr 23)
- Re: Cracking preshared keys Damir Rajnovic (Apr 23)
- Re: Cracking preshared keys Derek (Apr 24)
- Re: Cracking preshared keys Gary Flynn (Apr 24)
- Re: Cracking preshared keys Michael Thumann (Apr 24)
- Re: Cracking preshared keys Gary Flynn (Apr 24)
- Re: Cracking preshared keys Damir Rajnovic (Apr 23)
- Re: Cracking preshared keys David Wagner (Apr 24)
- Re: Cracking preshared keys Michael Thumann (Apr 24)
- Re: Cracking preshared keys Curt Sampson (Apr 25)
- Re: Cracking preshared keys Stefan Laudat (Apr 26)
- <Possible follow-ups>
- RE: Cracking preshared keys Rager, Anton (Anton) (Apr 24)
- Re: Cracking preshared keys hank (Apr 25)