ZDI-11-138: Webkit Undefined DOM Prototype Attach Remote Code Execution Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-11-138

April 19, 2011

-- CVSS:
9, (AV:N/AC:L/Au:N/C:P/I:P/A:C)

-- Affected Vendors:
WebKit

-- Affected Products:
WebKit WebKit

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-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of Apple Safari Webkit. User interaction is
required to exploit this vulnerability in that the target must visit a
malicious page or open a malicious file.

The specific flaw exists within the application's implementation of a
Frame element. When attaching this element to a document, the
application will duplicate a reference of an anonymous block. When
freeing the container holding the Frame element, the reference will
still be available. If an attacker can perform an explicit type change
of the contents the element this can then be leveraged to gain code
execution under the context of the application.

-- Vendor Response:
Webkit fix:
http://trac.webkit.org/changeset/67182

-- Disclosure Timeline:
2011-03-31 - Vulnerability reported to vendor
2011-04-19 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by:
    * wushi of team509

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