ZDI-11-139: Webkit Anonymous Frame Remote Code Execution Vulnerability

ZDI-11-139 (formerly ZDI-CAN-1035): Webkit Anonymous Frame Remote Code Execution
Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-11-139

April 19, 2011

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

– Affected Vendors:
WebKit

– Affected Products:
WebKit WebKit

– TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability by Digital Vaccine protection filter ID 11101.
For further product information on the TippingPoint IPS, visit:

http://www.tippingpoint.com

– 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 library's implementation of a frame
element. When parsing a malformed document embedded inside an SVG
document, the library will create an anonymous block around a frame
element in the block's contents. When freeing this anonymous block via
an assignment to the read-only .textContent attribute, a reference to
one of the child elements will still exist. Accessing this child element
can then lead to code execution under the context of the application.

– Vendor Response:
Webkit fix:
http://trac.webkit.org/changeset/81611

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

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

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