Message-ID: <4497A7F7.9040701@trifinite.org>
Date: Tue Jun 20 09:42:39 2006
From: martin.herfurt at trifinite.org (Martin Herfurt)
Subject: trifinite Security Advisory: Buffer Overrun in
 Toshiba Bluetooth Stack for Windows

trifinite Security Advisory: Buffer Overrun in Toshiba Bluetooth Stack
for Windows (TRSA00001)
http://trifinite.org/trifinite_advisory_toshiba.html

Author: 	Martin Herfurt <martin.herfurt (at) trifinite.org>
Organization: 	trifinite.org
Web: 		http://trifinite.org/

Summary
This advisory describes a vulnerability that affects Toshiba Bluetooth
Host Stack implementations up to version 4.0.23.
A vulnerability has been discovered that enables the attacker to
remotely perform a denial of service (DoS) against the host. This
vulnerability was discovered by members of the trifinite.group (Martin
Herfurt, Marcel Holtmann and Adam Laurie)

Affected Products
Hosts with the Toshiba Bluetooth Stack for Windows up to Version 4.0.23
Vulnerable Versions of this software ship with the following computers:
* Toshiba Computers with Bluetooth interface
* Dell Computers with Bluetooth module D350
* Sony Vaio Computers with Bluetooth Interface
* ASUS Computers with Bluetooth Interface
* and possibly other brands that use this stack

Details
The attacker is able to remotely cause a critical System Exception on
Windows XP hosts that results in an immidiate reboot of the system (Blue
Screen of Death). The crash is triggered through the host's Bluetooth
interface by an attack that has been introduced under the name BlueSmack
(http://trifinite.org/trifinite_stuff_bluesmack.html). By sending large
payloads with L2CAP Echo Requests, data is written to non-paged memory
areas. The driver causing this behaviour is TOSRFBD.SYS.

Impact
The attacker is able to remotely cause a critical system exception on
Windows hosts that results in an immidiate reboot of the system
(Bluescreen of Death). The attacker needs to be in physical proximity of
the device. Depending on the Bluetooth device class, Bluetooth Wireless
Technology typically covers a range 10 meters. This range can be
extended to distances of up to one mile by using directional antennas
that are connected to the attacker's equipment.

Obtaining Fixed Software
At the time of the publication of this advisory (20th of June 2006),
the vendor had more than four months for resolving the issue and did not
succeed. They have declined to comment on our submission. In the process
of disclosure, Microsoft and the Bluetooth SIG have also been informed
about the issue in April 2006.
At the time of writing this advisory, there is no version of the
enhanced data rate (EDR) capable Toshiba Bluetooth Stack for Windows
that is secure against the vulnerability described above. The latest
version of the stack which has been released in May 2006 and does not
address this vulnerability either.

Workarounds
As the attacker needs to know the Bluetooth device address of the host a
workaround is to switch the Bluetooth module into invisible mode. This
mode prevents the host from being discovered by attackers and allows
normal operation of Bluetooth devices that are bonded with the host.
Exploitation and Public Announcements
Besides the ability to remotely cause a blue screen, the ability to
execute arbitrary code on the accected machine cannot be confirmed.

Distribution
This advisory has been posted to the BugTraq, Full Disclosure and
BlueTraq mailing lists and is available as pdf document in the downloads
section of trifinite.org (http://trifinite.org/)

Revisison History
20th of June 2006: Initial release of document

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