ZDI-11-241: Webkit setAttributes attributeChanged Remote Code Execution Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-11-241

July 27, 2011

-- CVE ID:
CVE-2011-0254

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

-- Affected Vendors:
WebKit

-- Affected Products:
WebKit 

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability by Digital Vaccine protection filter ID 11481. 
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 the Webkit Library. 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 NamedNodeMap::setAttributes method
defined within the NamedNodeMap.cpp file distributed with WebKit. The
code responsible for copying attributes between DOM nodes does not
verify that a mutation may have occurred when an attribute's
attributeChanged method is called. By crafting a page that deletes
instances of that attribute when the above mentioned method is called
the code within setAttributes can be made to operate on freed objects.
An attacker can take advantage of this by spraying the heap in a way
that will not result in null pointers being referenced. This can lead to
arbitrary code execution under the context of the user running the
browser.

-- Vendor Response:
WebKit has issued an update to correct this vulnerability. More
details can be found at:
http://support.apple.com/kb/HT4808

-- Disclosure Timeline:
2011-04-19 - Vulnerability reported to vendor
2011-07-27 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by:
    * Anonymous

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