Public Vulnerability Reports

Microsoft Internet Explorer Object Handling Memory Corruption Vulnerability

11.10.11

BACKGROUND

Internet Explorer is a graphical web browser developed by Microsoft Corp. that has been included with Microsoft Windows since 1995. For more information about Internet Explorer, please the visit following website: http://www.microsoft.com/windows/internet-explorer/default.aspx

DESCRIPTION

Remote exploitation of a memory corruption vulnerability in Microsoft Corp.'s Internet Explorer could allow an attacker to execute arbitrary code with the privileges of the current user.

The vulnerability occurs when a Javascript event handler such as "onload" is set to a Javascript object's attributes or childNodes collection. A event object is created and this object's memory is later freed; however, a reference to the object remains. When the reference is later used to access the event object, this now-invalid memory is treated as a valid object. The corrupt object's vtable is used to make an indirect function call. This may result in the execution of arbitrary code.

ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user viewing the Web page. To exploit this vulnerability, a targeted user must load a malicious Web page created by an attacker. An attacker typically accomplishes this via social engineering or injecting content into compromised, trusted sites. After the user visits the malicious Web page, no further user interaction is needed.

DETECTION

Microsoft Internet Explorer 6 is vulnerable.

WORKAROUND

Microsoft suggested workarounds can be found under the workaround section of the following link:

http://www.microsoft.com/technet/security/bulletin/MS11-081.mspx

VENDOR RESPONSE

Microsoft has released fixes which addresses this issue. Information about downloadable vendor updates can be found by clicking on the URLs shown.

http://www.microsoft.com/technet/security/bulletin/MS11-081.mspx

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-1997 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

06/08/2011 Initial Vendor Notification
06/08/2011 Vendor Reply
10/11/2011 Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by gwslabs.com.

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LEGAL NOTICES

Copyright © 2011 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.