Public Vulnerability Reports

Motorola netOctopus Agent MSR Write Privilege Escalation Vulnerability

01.07.08

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/

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.

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.

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.

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.

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

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.

DISCLOSURE TIMELINE

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

CREDIT

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

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LEGAL NOTICES

Copyright © 2008 Verisign, Inc.

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