Trend Micro Tmxpflt.sys IOCTL 0xa0284403 Buffer Overflow Vulnerability
iDefense Security Advisory 10.25.07
http://labs.idefense.com/intelligence/vulnerabilities/
Oct 25, 2007
I. BACKGROUND
The Trend Micro AntiVirus scan engine provides AntiVirus capabilities to
desktop, server, and gateway systems. The engine is licensed to several
of Trend Micro's OEM partners. More information is available on Trend
Micro's web site at the following URL.
http://www.trendmicro.com/
II. DESCRIPTION
Local exploitation of a buffer overflow vulnerability within
Tmxpflt.sys, as included with Trend Micro Inc.'s AntiVirus engine,
could allow an attacker to execute arbitrary code in kernel context.
This vulnerability specifically exists due to insecure permissions on
the "\\.\Tmfilter" DOS device interface. The permissions on this device
allow "Everyone" write access. This allows a locally logged-in user to
access functionality intended for privileged use only.
Additionally, the IOCTL handler of this DOS device interface for IOCTL
0xa0284403 does not validate the length of attacker-supplied content
when copying to a fixed-size buffer. As such, it is possible to execute
attacker-supplied code in the context of the kernel.
III. ANALYSIS
Exploitation allows an attacker to elevate their privileges by
overwriting arbitrary system memory or executing code within kernel
context. In order to exploit this vulnerability, an attacker would need
the ability to open a handle to the "\\.\Tmfilter" DOS device interface.
IV. DETECTION
iDefense Labs has confirmed the existence of this vulnerability in
following Trend Micro Products:
Trend Micro's PC-Cillin Internet Security 2007
Tmxpflt.sys version 8.320.1004 and 8.500.0.1002
All products using Trend Micro's scan engine such as Trend Micro
ServerProtect, Trend Micro OfficeScan are also suspected to be
vulnerable.
V. WORKAROUND
Removing write permissions for "Everyone" prevents unprivileged access
to the vulnerable code. iDefense confirmed that the virus scanning
engine was still able to detect viruses. Although no side effects were
witnessed during Lab tests, normal functionality may be disrupted.
VI. VENDOR RESPONSE
Trend Micro has addressed this vulnerability with the release of version
8.550-1001 of their scan engine. For more information, visit the
following URL.
http://esupport.trendmicro.com/support/viewxml.do?ContentID=1035793
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-4277 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
08/06/2007 Initial vendor notification
08/06/2007 Initial vendor response
10/25/2007 Coordinated public disclosure
IX. CREDIT
This vulnerability was reported to iDefense by RubÃn Santamarta of
reversemode.com.
Get paid for vulnerability research
http://labs.idefense.com/methodology/vulnerability/vcp.php
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http://labs.idefense.com/
X. LEGAL NOTICES
Copyright  2007 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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