iDefense Security Advisory 07.20.11 http://labs.idefense.com/intelligence/vulnerabilities/ Jul 20, 2011 I. BACKGROUND WebKit is an open source web browser engine. It is currently used by Apple Inc.'s Safari browser, as well as by Google's Chrome browser. For more information, see the vendor's site at the following link. http://webkit.org/ II. DESCRIPTION Remote exploitation of a memory corruption vulnerability in WebKit, as included with multiple vendors' browsers, could allow an attacker to execute arbitrary code with the privileges of the current user. Scalable Vector Graphics (SVG) is an XML based file format used to describe two dimensional vector graphics. It defines both a markup language, and a JavaScript interface. When parsing a series of SVG tags, and then manipulating them via JavaScript, Safari fails to handle exceptional conditions. It is possible to trigger a use after free vulnerability by manipulating the animVal property of various SVG tags. This leaves a C++ object pointer in an inconsistent state, which can lead to the execution of arbitrary code. III. 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 webpage 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. IV. DETECTION Safari versions prior to 5.1 and 5.0.6 are vulnerable. V. WORKAROUND Disabling JavaScript is an effective workaround for this vulnerability. VI. VENDOR RESPONSE Apple Inc. has released patches which addresses this issue. For more information, consult their advisory at the following URL: http://support.apple.com/kb/HT4808 VII. CVE INFORMATION The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0240 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 12/01/2010 Initial Vendor Notification 12/01/2010 Initial Vendor Reply 07/20/2011 Coordinated Public Disclosure IX. CREDIT This vulnerability was reported to iDefense by wushi of team509. Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events http://labs.idefense.com/ X. LEGAL NOTICES Copyright © 2011 Verisign. Permission is granted for the redistribution of this alert electronically. It may not be edited in any way without the express written consent of iDefense. If you wish to reprint the whole or any part of this alert in any other medium other than electronically, please e-mail customerservice@idefense.com for permission. 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.