Public Vulnerability Reports

Multiple Vendor WebKit frameset style Heap Corruption Vulnerability

07.20.11

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/

DESCRIPTION

Remote exploitation of a heap based buffer overflow vulnerability in WebKit, as included with Apple Inc.'s Safari Web browser, could allow an attacker to execute arbitrary code with the privileges of the current user.

The vulnerability occurs when parsing a frameset element with a malicious style attribute. Specifically, by setting the padding property to certain values it is possible to trigger a heap based memory corruption vulnerability. 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 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.

DETECTION

Safari versions prior to 5.1 and 5.0.6 are vulnerable.

WORKAROUND

iDefense is currently unaware of an effective workaround for this vulnerability as it occurs in the core parsing code. However, disabling scripting will make the vulnerability more difficult to exploit using known techniques.

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

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0223 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

02/25/2011 Initial Vendor Notification
02/25/2011 Initial Vendor Reply
07/20/2011 Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by Jose A. Vazquez of {http://spa-s3c.blogspot.com}.

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LEGAL NOTICES

Copyright © 2011 Verisign, Inc.

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