iDefense Security Advisory 03.31.08
http://labs.idefense.com/intelligence/vulnerabilities/
Mar 31, 2008

I. BACKGROUND

Macrovision InstallShield InstallScript One-Click Install (OCI) is a web
based installer technology that allows software publishers to distribute
minimal installer packages which allow end users to select components to
install. Upon first visiting such a website, the user is prompted to
install the ActiveX control. More information can be found on the
vendor's site at the following URL.

http://www.macrovision.com/products/installation/installshield.htm

II. DESCRIPTION

Remote exploitation of an untrusted library loading vulnerability in
Macrovision's InstallShield InstallScript One-Click Install ActiveX
control allows remote attackers to execute code with the privileges of
the currently logged in user.

InstallShield InstallScript "One-Click Install" is implemented in an
ActiveX control with the following properties:

  File: %WINDIR%\Downloaded Program Files\setup.exe
  CLSID: 53D40FAA-4E21-459f-AA87-E4D97FC3245A

This control is marked "safe for scripting".

When a user visits a website from which a web install can be performed,
the ActiveX control downloads and loads several DLL files from the
remote website. Since no sanity checks are performed on the DLL files,
an attacker can substitute specially crafted libraries that will
execute arbitrary code when loaded.

III. ANALYSIS

Exploitation allows attackers to execute arbitrary code with the
privileges of the currently logged-in user. In order for exploitation
to occur, users would be required to have a vulnerable version of the
ActiveX control installed and be lured to a malicious site.

IV. DETECTION

iDefense confirmed this vulnerability exists in version 12.0 of the
Macrovision InstallShield InstallScript One-Click Install ActiveX
Control. Previous versions of the control are reported to be vulnerable
to variations of this attack. Previous versions are known to use
different CLSIDs.

V. WORKAROUND

Administrators can set the kill-bit for the vulnerable ActiveX control
with the following .reg file. This will prevent the control from
loading within Internet Explorer.

  Windows Registry Editor Version 5.00
 
  [HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Internet Explorer\ActiveX
Compatibility\{53D40FAA-4E21-459f-AA87-E4D97FC3245A}]
  "Compatibility Flags"=dword:00000400

VI. VENDOR RESPONSE

Macrovision has addressed this vulnerability by releasing a hotfix for
the following products.

  FLEXnet InstallShield 12 Professional (with InstallShield 12 SP2)
  FLEXnet InstallShield 12 Premier (with InstallShield 12 SP2)

For more information, consult their Knowledge Base article at the
following URL.

http://knowledge.macrovision.com/selfservice/microsites/search.do?cmd=displayKC&externalId=Q113640

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2007-5661 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

01/08/2007  Initial vendor notification
04/17/2007  Second vendor notification
04/18/2007  Initial vendor response
03/31/2008  Coordinated public disclosure

IX. CREDIT

The discoverer of this vulnerability wishes to remain anonymous.

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X. LEGAL NOTICES

Copyright © 2008 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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