QNX Neutrino RTOS phgrafx Command Buffer Overflow

iDefense Security Advisory 02.07.06
http://www.idefense.com/intelligence/vulnerabilities/display.php?id=384
February 7, 2006

I. BACKGROUND

QNX Software Systems Ltd.'s Neutrino RTOS (QNX) is a real-time operating
system designed for use in embedded systems. More information is
available at:

  http://www.qnx.com/products/rtos/

II. DESCRIPTION

Local exploitation of a buffer overflow in QNX Neutrino RTOS's (QNX)
'phgrafx' 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 'phgrafx'. A
string larger than approximately 1,000 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

Successful exploitation provides local attackers with super-user
privileges on the affected system allowing for complete control.

IV. DETECTION

iDefense has confirmed the existence of these vulnerabilities in QNX
Neutrino RTOS version 6.2.1. 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

08/24/2004  Initial vendor notification
02/07/2006  Public disclosure

IX. CREDIT

Knud Hojgaard (http://kokanin.dtors.net) is credited with this
discovery.

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X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

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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.
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