Subject: [eap] Vulnerability in TLS-based EAP protocols

From: Yao Zhao <[email-masked]>
Date: Mon, 24 Nov 2008 13:19:28 -0600

Description of issue
We found that for TLS-based EAP protcols (such as EAP-TLS, EAP-TTLS and
PEAP) can be easily attacked so that the users cannot got authenticated.
The attack on PEAP was implemented and tested on a large university
wireless networks using PEAP.

Submitter name: Yao Zhao

Submitter email address: [email-masked]

Date first submitted: Nov 24, 2008

Reference: www.cs.northwestern.edu/~yzhao/papers/errormsg.pdf
<http://www.cs.northwestern.edu/%7Eyzhao/papers/errormsg.pdf>

Length description of problem:

The attack targets the TLS protocol, which is widely used in many EAP
protocols such as PEAP, EAP-TLS, EAP-TTLS and EAP-FAST. Therefore, all
the TLS based EAP protocols will be vulnerable to this attack.

An attacker sniffs the communication between the wireless client and the
access point, inspecting the authentication procedure through the
Handshake protocol of TLS. Triggered by some messages, the attacker
spoofs a corresponding FATAL ALERT messages to make the TLS
authentication fail. Specifically, the attacker can spoof to be either
the authentication server or the client to fool the other side.

Please see more details in the pdf file provided above.

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From: Bernard Aboba <[email-masked]>
Date: Mon, 24 Nov 2008 13:58:21 -0800

One question is whether the solutions proposed in the paper, if implemented,
would have much of an impact on the entire surface area of DoS vulnerabilities
in WLANs. 

Attacks on the 802.11 infrastructure (e.g. spoofed Association-Requests)
are even easier to mount than EAP attacks, and can impact the entire ESS
(not just the particular BSSID that is being attacked).  Moreover, those
attacks cannot be protected against without reworking the 802.11i state
machine (e.g. you need protected Association-Requests, which would require
authentication prior to association). 

Date: Mon, 24 Nov 2008 13:19:28 -0600
From: [email-masked]
To: [email-masked]
Subject: [eap] Vulnerability in TLS-based EAP protocols

Description
of issue

We found that for TLS-based EAP protcols (such as EAP-TLS, EAP-TTLS and
PEAP) can be easily attacked so that the users cannot got
authenticated. The attack on PEAP was implemented and tested on a large
university wireless networks using PEAP.

Submitter name: Yao Zhao

An attacker sniffs the communication between the wireless client and
the access point, inspecting the authentication procedure through the
Handshake protocol of TLS. Triggered by some messages, the attacker
spoofs a corresponding FATAL ALERT messages to make the TLS
authentication fail. Specifically, the attacker can spoof to be either
the authentication server or the client to fool the other side.