QNX Neutrino RTOS passwd Command Buffer Overflow

iDefense Security Advisory 02.07.06
http://www.idefense.com/intelligence/vulnerabilities/display.php?id=388
February 7, 2006

I. BACKGROUND

QNX Neutrino RTOS is a real-time operating system designed for use in
embedded systems. More information about is available at
http://www.qnx.com/products/ps_neutrino.

II. DESCRIPTION

Local exploitation of a buffer overflow in QNX Neutrino RTOS's (QNX)
'passwd' command allows attackers to gain root privileges. The problem
specifically exists in the parsing of a long string passed as the first
argument to the set user id (setuid) binary 'passwd'. The 'passwd'
command is intended for changing a users password. A string larger then
approximately 4000 bytes causes a stack overflow directly overwriting
the stored return address and allowing an attacker to seize CPU control
and eventually execute arbitrary code under root privileges.

III. ANALYSIS

Any authenticated local attacker can exploit this vulnerability to gain
super-user (root) privileges on the affected system.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities in QNX
Neutrino RTOS version 6.2.0. Earlier versions are suspected to be
susceptible to exploitation as well.

V. WORKAROUND

Clear the set user id or execute bits from the affected binary or remove
it entirely.

VI. VENDOR RESPONSE

The vendor has not responded to communication regarding this issue.

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

06/04/2004  Initial vendor notification
02/07/2006  Public disclosure

IX. CREDIT

Texonet (www.texonet.com) is credited with this discovery.

Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp

Free tools, research and upcoming events
http://labs.idefense.com

X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice@idefense.com for permission.

Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.