QNX RTOS 6.3.0 rc.local Insecure File Permissions Vulnerability

iDefense Security Advisory 02.07.06
http://www.idefense.com/intelligence/vulnerabilities/display.php?id=387
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 design vulnerability in QNX Software Systems QNX
Realtime Operating System (RTOS) allows attackers to execute arbitrary
commands with root privileges.

The problem specifically exists because QNX RTOS 6.3.0 ships with world
writable permissions on the file /etc/rc.d/rc.local. This file is parsed
and executed with root privileges upon startup. An attacker can insert
commands into this file which will then be executed once the operating
system is restarted.

III. ANALYSIS

Successful exploitation allows local attackers to execute arbitrary
commands with root privileges. This vulnerability when combined with a
local system-wide denial of service vulnerability allows an attacker to
gain immediate root privileges.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in QNX RTOS
version 6.3.0. Version 6.0 was also tested and found to not be
vulnerable.

V. WORKAROUND

Set more restrictive permissions on the rc.local file:

  chmod 644 /etc/rc.d.rc.local

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

12/24/2004   Initial vendor notification
02/07/2006   Public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2006 iDefense, Inc.

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at the time of publishing based on currently available information. Use
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