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.
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.
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.
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.
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.
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.
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.
08/06/2007 Initial vendor notification
08/06/2007 Initial vendor response
10/25/2007 Coordinated public disclosure
This vulnerability was reported to iDefense by Rubén Santamarta of reversemode.com.
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Copyright © 2007 Verisign, Inc.
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