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Multiple Vendor WebKit JRE Plugin Module Use-after-Free Vulnerability

01.02.13

BACKGROUND

WebKit is an open-source Web browser engine. It is currently used by Apple Inc.'s Safari browser and Google Inc.'s Chrome browser. For more information, see the vendor's site at the following link:

http://webkit.org/

DESCRIPTION

Remote exploitation of a use-after-free vulnerability in WebKit, as included with multiple vendors' browsers, could allow an attacker to execute arbitrary code with the privileges of the current user.

This vulnerability occurs due to an interaction between the JRE plug-in for WebKit-based browsers and the browser's JavaScript engine. When DOM nodes containing applet elements are manipulated via JavaScript, a reference counting error occurs. This results in the plug-in module being unloaded while a return address pointing inside of it still resides on the stack. The result is that a stale return address is used when control returns from an asynchronous JavaScript Event Handler. This can lead to 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 that an attacker has created. 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

JRE 7 Update 11 and prior, 6 Update 38 and prior are vulnerable.

WORKAROUND

Disabling the JRE plug-in is an effective workaround for this vulnerability.

VENDOR RESPONSE

Oracle has released a fix which addresses this issue. For more information, consult their advisory at the following URL:

http://www.oracle.com/technetwork/topics/security/javacpufeb2013-1841061.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2012-1541 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

04/04/2012 Initial Vendor Notification
04/19/2012 Initial Vendor Reply
02/01/2013 Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by wushi of team509.

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LEGAL NOTICES

Copyright © 2013 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.