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

04.17.07

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

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.

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.

DETECTION

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

WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

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

CVE INFORMATION

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

DISCLOSURE TIMELINE

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

CREDIT

This vulnerability was discovered by Jun Mao (iDefense Labs).

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LEGAL NOTICES

Copyright © 2007 Verisign, 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.