Date: 14 November 2007
Click here for printable version
Click here for PGP verifiable version
-----BEGIN PGP SIGNED MESSAGE-----
AUSCERT External Security Bulletin Redistribution
ESB-2007.0909 -- [Win]
Novell NetWare Client Local Privilege Escalation Vulnerability
14 November 2007
AusCERT Security Bulletin Summary
Product: Novell NetWare Client
Operating System: Windows
Impact: Administrator Compromise
Access: Existing Account
CVE Names: CVE-2007-5667
- --------------------------BEGIN INCLUDED TEXT--------------------
iDefense Security Advisory 11.12.07
Nov 12, 2007
The Novell Client software provides a workstation with access to Novell
NetWare networks as well as Novell Open Enterprise Server (OES)
services. Novell Clients can access the full range of Novell services
such as authentication via Novell eDirectory, network browsing and
service resolution, and secure and reliable file system access. More
information about the Novel Client can be found on the vendor's site at
the following URL.
Local exploitation of an input validation error vulnerability within
Novell NetWare Client could allow an unprivileged attacker to execute
arbitrary code within the kernel.
When the Novell NetWare Client is installed on a Windows based operating
system, the driver nwfilter.sys will be loaded at system startup. This
driver allows any user to open the device "\.\nwfilter" and issue
IOCTLs with a buffering mode of METHOD_NEITHER.
The problem specifically exists because the driver allows untrusted user
mode code to pass kernel addresses as arguments to the driver. With
specially constructed input, a malicious user can use functionality
within the driver to patch kernel addresses and execute arbitrary code
within kernel mode.
Exploitation of this vulnerability allows an unprivileged local user to
patch and execute arbitrary code within the kernel. In order to exploit
the vulnerability, an attacker needs to be able to log in to the target
machine and execute a specially crafted executable.
iDefense has confirmed the existence of this vulnerability in
nwfilter.sys, file version 188.8.131.52, as included with Novell's NetWare
Client 4.91 SP4. Other versions are suspected vulnerable as well.
iDefense is currently unaware of any workaround for this issue.
VI. VENDOR RESPONSE
Novell has addressed this vulnerability by releasing patches that remove
the "nwfilter.sys" driver. For more information, consult Novell's
advisory at the following URL.
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-5667 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
VIII. DISCLOSURE TIMELINE
09/25/2007 Initial vendor notification
09/25/2007 Initial vendor response
11/12/2007 Coordinated public disclosure
This vulnerability was reported to iDefense by Stephen Fewer of Harmony
Get paid for vulnerability research
Free tools, research and upcoming events
X. LEGAL NOTICES
Copyright © 2007 iDefense, 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 e-mail firstname.lastname@example.org 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.
- --------------------------END INCLUDED TEXT--------------------
You have received this e-mail bulletin as a result of your organisation's
registration with AusCERT. The mailing list you are subscribed to is
maintained within your organisation, so if you do not wish to continue
receiving these bulletins you should contact your local IT manager. If
you do not know who that is, please send an email to email@example.com
and we will forward your request to the appropriate person.
NOTE: Third Party Rights
This security bulletin is provided as a service to AusCERT's members. As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content. The decision to follow or act on information or advice
contained in this security bulletin is the responsibility of each user or
organisation, and should be considered in accordance with your organisation's
site policies and procedures. AusCERT takes no responsibility for consequences
which may arise from following or acting on information or advice contained in
this security bulletin.
NOTE: This is only the original release of the security bulletin. It may
not be updated when updates to the original are made. If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the author's website to ensure that the information is still current.
Contact information for the authors of the original document is included
in the Security Bulletin above. If you have any questions or need further
information, please contact them directly.
Previous advisories and external security bulletins can be retrieved from:
If you believe that your computer system has been compromised or attacked in
any way, we encourage you to let us know by completing the secure National IT
Incident Reporting Form at:
Australian Computer Emergency Response Team
The University of Queensland
Internet Email: firstname.lastname@example.org
Facsimile: (07) 3365 7031
Telephone: (07) 3365 4417 (International: +61 7 3365 4417)
AusCERT personnel answer during Queensland business hours
which are GMT+10:00 (AEST).
On call after hours for member emergencies only.
-----BEGIN PGP SIGNATURE-----
-----END PGP SIGNATURE-----