ZDI-11-099: Apple Webkit Font Glyph Layout Remote Code Execution Vulnerability

http://www.zerodayinitiative.com/advisories/ZDI-11-099

March 2, 2011

-- CVE ID:
CVE-2011-0133

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

-- Affected Vendors:
Apple

-- Affected Products:
Apple WebKit

-- TippingPoint(TM) IPS Customer Protection:
TippingPoint IPS customers have been protected against this
vulnerability by Digital Vaccine protection filter ID 10870. 
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-- Vulnerability Details:
This vulnerability allows remote attackers to execute arbitrary code on
vulnerable installations of Apple Safari's 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 way the application handles floating
blocks in certain situations. When performing layout operations for a
floating block produced by a pseudo-element, the application will
attempt to access glyph data that hasn't been fully assigned into the
glyph data hashmap. Due to this type being incomplete, this can lead to
code execution under the context of the application.

-- Vendor Response:
Apple has issued an update to correct this vulnerability. More
details can be found at:
http://support.apple.com/kb/HT4554

-- Disclosure Timeline:
2010-10-18 - Vulnerability reported to vendor
2011-03-02 - Coordinated public release of advisory

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

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