[Full-disclosure] iDefense Security Advisory 07.31.08: Apple Mac OS X CoreGraphics PDF Type1 Font Integer Overflow Vulnerability



iDefense Security Advisory 07.31.08
http://labs.idefense.com/intelligence/vulnerabilities/
Jul 31, 2008

I. BACKGROUND

Mac OS X is a Unix operating system built from the XNU kernel. Mac OS X
provides all the standard Unix capabilities and tools with an
additional GUI component. For more information, see the vendor's site
found at the following link URL.

http://www.apple.com/macosx/

II. DESCRIPTION

Remote exploitation of an integer overflow vulnerability in Apple Inc.'s
Mac OS X could allow an attacker to execute arbitrary code with the
privileges of the currently logged in user.

This vulnerability exists due to the way PDF files containing Type 1
fonts are handled. When processing a font with an overly large length,
integer overflow could occur. This issue leads to heap corruption which
can allow for arbitrary code execution.

III. ANALYSIS

Exploitation of this issue allows an attacker to execute arbitrary code.
An attacker could exploit this issue via multiple attack vectors. The
most appealing vector for attack is Safari. An attacker could host a
malformed PDF file on a website and entice a targeted user to open a
URL. Upon opening the URL in Safari the PDF file will be automatically
parsed and exploitation will occur. While this is the most appealing
attack vector, the file can also be attached to an e-mail. Any
application which uses the Apple libraries for file open dialogs will
crash upon previewing the malformed PDF document.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Mac OS X
version 10.5.2. Previous versions may also be affected.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

VI. VENDOR RESPONSE

Apple addressed this vulnerability within their Mac OS X 2008-005
security update. More information is available at the following URL.

http://support.apple.com/kb/HT2647

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2008-2322 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org/), which standardizes names for
security problems.

VIII. DISCLOSURE TIMELINE

07/09/2008 Initial vendor notification
07/10/2008 Initial vendor response
07/31/2008 Public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Pariente Kobi.

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X. LEGAL NOTICES

Copyright © 2008 iDefense, Inc.

Permission is granted for the redistribution of this alert
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Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct,
indirect, or consequential loss or damage arising from use of, or
reliance on, this information.

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