QNX crrtrap possible race condition vulnerability
*** 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
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