ZDI-10-257: Apple Webkit WholeText Integer Overflow Remote Code Execution Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-10-257

November 23, 2010

-- CVE ID:
CVE-2010-3812

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

-- Affected Vendors:
Apple

-- Affected Products:
Apple WebKit

-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of Apple 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 wholeText method of the Text
element. When calculating the total size of all the text containing it,
the application will wrap a 32-bit integer. The application will use
this in an allocation and then later use a different value for
populating the buffer. This can lead to code execution under the context
of the application.


-- Vendor Response:
Apple states:
iOS 4.2: http://support.apple.com/kb/HT4456

-- Disclosure Timeline:
2010-08-12 - Vulnerability reported to vendor
2010-11-23 - Coordinated public release of advisory

-- Credit:
This vulnerability was discovered by:
    * J23 (http://twitter.com/HansJ23)

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