McAfee VirusScan On-Access Scanner Long Unicode File Name Buffer Overflow

iDefense Security Advisory 04.17.07
http://labs.idefense.com/intelligence/vulnerabilities/
Apr 17, 2007

I. BACKGROUND

McAfee VirusScan is an AntiVirus application that offers protection
against the latest computer virus threats. More information can be
found on the vendor's site at the following URL.

http://www.mcafee.com/us/enterprise/products/anti_virus/file_servers_desktops/virusscan_enterprise_80i.html

II. DESCRIPTION

Remote exploitation of a buffer overflow vulnerability in McAfee's
VirusScan Antivirus application allows attackers to disable the
On-Access scanner or potentially execute arbitrary code with SYSTEM
privileges.

The McAfee On-Access scanner component contains a common software flaw
that leads to heap corruption when dealing with overly long file names
that contain multi-byte characters.

This flaw only manifests itself when the target system has East Asia
language files installed and the default Unicode codepage is set to a
language which contains multi-byte characters such as Chinese.

III. ANALYSIS

Exploitation allows attackers to disable the On-Access Scanner component
of McAfee VirusScan or potentially execute arbitrary code with SYSTEM
privileges.

In order to exploit this vulnerability, an attacker needs to be able to
place a file with an overly long file name on the victims computer. The
file name would have to contain multi-byte characters such as Chinese
native characters. If the On-Access scanner is enabled, simply hovering
the mouse over the file to view the file properties or attempting to
open the file will trigger the overflow.

Standard archive manipulation programs such as WinZip and Windows
Compressed Folder viewer cannot handle files capable of exploiting this
vulnerability.

IV. DETECTION

iDefense has confirmed this vulnerability in McAfee VirusScan 8.0
Enterprise. Previous versions are suspected vulnerable as well.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

McAfee has addressed this vulnerability in Patch 12 of VirusScan
Enterprise 8.0i. They recommend installing the latest available patch
(Patch15). More information is available in McAfee's Security Bulletin
612750 at the following URL.

https://knowledge.mcafee.com/SupportSite/dynamickc.do?externalId=612750&command=show&forward=nonthreadedKC

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

02/08/2007  Initial vendor notification
02/08/2007  Initial vendor response
04/17/2007  Coordinated public disclosure

IX. CREDIT

This vulnerability was discovered by iDefense Labs.

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http://labs.idefense.com/methodology/vulnerability/vcp.php

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X. LEGAL NOTICES

Copyright © 2007 iDefense, Inc.

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at the time of publishing based on currently available information. Use
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