Trend Micro PC-Cillin Internet Security Insecure File Permission 
Vulnerability

iDefense Security Advisory 12.14.05
www.idefense.com/application/poi/display?id=351&type=vulnerabilities
December 14, 2005

I. BACKGROUND

Trend Micro PC-Cillin Internet Security is antivirus protection software
for home and business use. It provides complete protection, detection
and elimination of thousands of computer viruses, worms, and Trojan
Horse programs.

II. DESCRIPTION

Local exploitation of an insecure permission vulnerability in multiple
Trend Micro Inc. products allows attackers to escalate privileges or
disable protection.

The vulnerabilities specifically exist in the default Access Control
List (ACL) settings that are applied during installation. When an
administrator installs an affected Trend Micro product, the default ACL
allows any user to modify the installed files. Due to the fact that some
of the programs run as system services, a user could replace an
installed Trend Micro product file with their own malicious code, and
the code would be executed with system privileges.

III. ANALYSIS

Successful exploitation allows local attackers to escalate privileges to
the system level. It is also possible to use this vulnerability to
simply disable protection by moving all of the executable files so that
they cannot start upon a reboot. Once disabled, the products are no
longer able to provide threat mitigation, thus opening the machine up to
attack.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Trend
Micro PC-Cillin Internet Security 2005 version 12.00 build 1244. It is
suspected that previous versions are also vulnerable. It has been
reported that InterScan VirusWall, InterScan eManager and Office Scan
are also vulnerable.

V. WORKAROUND

Apply proper Access Control List settings to the directory that the
affected Trend Micro product is installed in. The ACL rules be set so
that no regular users can modify files in the directory.

VI. VENDOR RESPONSE

"Trend Micro has become aware of a vulnerability related to PC-CILLIN
12. PC-cillin12 does not work correctly when configuration file and the
registry are erased intentionally.

We will release PC-cillin12.4 in December 14, 2005 by AU server. This
release will be included short term solution of changing ACL to User
authority for configuration file and registry.

And

We will create a tool for changing ACL to User authority for
configuration file and registry.

This tool can be used for both PC-cillin12 and PC-cillin14 as a same
program."

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2005-3360 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

10/27/2005 Initial vendor notification
10/27/2005 Initial vendor response
12/14/2005 Public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

Get paid for vulnerability research
http://www.iDefense.com/poi/teams/vcp.jsp

X. LEGAL NOTICES

Copyright © 2005 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.