Vulnerability Note VU#485961

Acer AcerCtrls.APlunch ActiveX Control fails to properly restrict access to methods

Overview

The Acer AcerCtrls.APlunch ActiveX control contains methods that can allow a remote, unauthenticated attacker to run arbitrary commands on a vulnerable system.

I. Description

The Acer AcerCtrls.APlunch ActiveX control is provided by acerctrl.ocx. It contains a method called Run(), which takes two parameters: Driveand FileName. Although the control is not inherently marked as safe for scripting via the IObjectSafety interface, it may be distributed with the appropriate Implemented Categories registry key to make it safe for scripting. This means that a web page in Internet Explorer can call the Run() method of the control.

Note that this vulnerability is similar to but not the same issue as VU#221700. This control has different parameters and uses a different CLSID that is not included in the killbits provided with Microsoft Security Bulletin MS07-027.

II. Impact

By convincing a victim to view an HTML document (web page, HTML email, or email attachment), an attacker could run arbitrary commands with the privileges of the user running IE.

III. Solution

We are currently unaware of a practical solution to this problem. Please consider the following workarounds:

Disable the Acer AcerCtrls.APlunch ActiveX control in Internet Explorer

The Acer AcerCtrls.APlunch ActiveX control can be disabled in Internet Explorer by setting the kill bit for the following CLSID:

{3895DD35-7573-11D2-8FED-00606730D3AA}

More information about how to set the kill bit is available in Microsoft Support Document 240797. Alternatively, the following text can be saved as a .REG file and imported to set the kill bit for this control:

Windows Registry Editor Version 5.00

[HKEY_LOCAL_MACHINESOFTWAREMicrosoftInternet ExplorerActiveX Compatibility{3895DD35-7573-11D2-8FED-00606730D3AA}]
"Compatibility Flags"=dword:00000400
[HKEY_LOCAL_MACHINESOFTWAREWow6432NodeMicrosoftInternet ExplorerActiveX Compatibility{3895DD35-7573-11D2-8FED-00606730D3AA}]
"Compatibility Flags"=dword:00000400

Disable ActiveX

Disabling ActiveX controls in the Internet Zone (or any zone used by an attacker) appears to prevent exploitation of this and other ActiveX vulnerabilities. Instructions for disabling ActiveX in the Internet Zone can be found in the "Securing Your Web Browser" document.

Systems Affected

Vendor	Status	Date Notified	Date Updated
Acer	Vulnerable	2007-05-09	2009-08-17

References

http://www.kb.cert.org/vuls/id/221700
http://vuln.sg/acerlunchapp-en.html
http://support.microsoft.com/kb/240797

Credit

Thanks to Michael Costa of Crosshair Information Technology & Security LLC for reporting this vulnerability.

This document was written by Will Dormann.

Other Information

Date Public:	2009-08-16
Date First Published:	2009-08-18
Date Last Updated:	2009-08-18
CERT Advisory:
CVE-ID(s):	CVE-2009-2627
NVD-ID(s):	CVE-2009-2627
US-CERT Technical Alerts:
Metric:	5.06
Document Revision:	13