*** rfdslabs security advisory ***

Title: QNX crrtrap possible race condition vulnerability [RLSA_04-2004]

Versions: QNX RTP 6.1 (possibly others)

Vendor: http://www.qnx.com

Date: Sep 13 2004

Author: Julio Cesar Fort <julio at rfdslabs com br>

1. Introduction

crrtrap is a tool to detect video hardware and starts the correct driver for

QNX.

2. Details

crttrap does a sequence of commands before calls 'io-graphics', an external

program part of Photon. Because of this, there is a theorical race condition

vulnerability.

--

(1) /bin/cd /usr/photon/bin

(*)

(2) io-graphics [arguments]

--

This spot (*) is where the race condition lies. If we are able to modify $PATH

in the exact moment before crrtrap calls step 2, we could obtain local root

priviledges because it will execute 'io-graphics' (our code) looking for it in

/tmp directory.

If an attacker writes a code to neverend loop changing everytime $PATH and runs

it into background, there is a theorical possiblility to modify environment and

trick crttrap.

3. Solution

QNX Software Systems was contacted in september 8th but vendor didn't reply.

It seems they don't care much about security (they don't even have a security

staff e-mail, but SALES e-mail adddress is everywhere at qnx.com!).

4. Timeline

26 Aug 2004: Vulnerability detected;

08 Sep 2004: rfdslabs contacts QNX: no success;

Thanks to DataStorm Technologies and some stranger in mobius.qnx.com who was

intersted in rfdslabs.com.br.

www.rfdslabs.com.br - computers, sex, humand mind, music and more

Recife, PE, Brazil

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