iDefense Security Advisory 01.07.08
http://labs.idefense.com/intelligence/vulnerabilities/
Jan 07, 2008

I. BACKGROUND

Motorola netOctopus is an asset management agent. It is used to deploy
software, monitor performance, and configure client machines from a
central administrative console. More information can be found on the
vendor's site at the following URL.

http://www.netopia.com/software/products/netoctopus/

II. DESCRIPTION

Local exploitation of a privilege escalation vulnerability in Motorola
Inc.'s netOctopus could allow an attacker to execute arbitrary code in
kernel context.

The netOctopus Agent software is supposed to be installed on all client
machines. It includes a driver, nantsys.sys, that is loaded at system
boot time. This driver exposes a device interface, \\.\NantSys, that is
writable by all users.

This driver includes functionality for reading and writing arbitrary CPU
Model Specific Registers (MSRs). Changing MSR values allows tuning of
various low level CPU operations. By modifying SYSENTER_EIP_MSR, is is
possible to execute arbitrary attacker supplied code in kernel context
by executing a sysenter instruction.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary
code in kernel context. Unsuccessful attempts may result in a system
crash. However, due to the nature of the vulnerability exploitation is
extremely reliable.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in version
5.0.0.115 of the nantsys.sys driver as included with netOctopus version
5.1.2 build 1011. Previous versions may also be affected.

V. WORKAROUND

Remove write permissions for the Everyone group for the \\.\NantSys
device. This can be accomplished by using a tool like WinObj. This will
prevent regular users from writing to the device.

VI. VENDOR RESPONSE

To address this vulnerability, Motorola Inc. has made a script available
to remove the affected driver from the system. For more information,
consult their advisory at the following URL.

http://www.netopia.com/support/software/technotes/netoctopus/Removing_the_nantsys_Driver.pdf
http://www.netopia.com/support/software/technotes/netoctopus/removeNantsys.vbs

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-5761 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

09/07/2007  Initial vendor notification
09/07/2007  Initial vendor response
01/07/2008  Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Stephen Fewer of Harmony
Security (www.harmonysecurity.com).

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X. LEGAL NOTICES

Copyright © 2008 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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