Public Vulnerability Reports

QNX Neutrino RTOS phfont Race Condition Vulnerability



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:


Local exploitation of a race condition vulnerability in QNX Neutrino
RTOS's (QNX) phfont command allows attackers to gain root privileges.

QNX Neutrino RTOS is a real-time operating system designed for use in
embedded systems. The problem specifically exists because phfont spawns
another command, phfontphf, without proper sanity checking. A local
attacker can create a malicious replacement for this command and cause
it to be executed in place of the original by manipulating the PHFONT
and PHOTON2_PATH environment variables. phfont is installed set user id
root by default.


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


iDefense has confirmed the existence of these vulnerabilities in QNX
Neutrino RTOS version 6.2.1. Earlier versions are also suspected to be
susceptible to exploitation.


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


The vendor has not responded to communication regarding this issue.


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


09/29/2004   Initial vendor notification
02/07/2006   Public disclosure


Knud Hojgaard ( is credited with this discovery.

Get paid for vulnerability research

Free tools, research and upcoming events


Copyright © 2006 Verisign, 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 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.