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iDefense Security Advisory 12.04.08: Sun Java JRE TrueType Font Parsing Heap Overflow Vulnerability



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iDefense Security Advisory 12.02.08
http://labs.idefense.com/intelligence/vulnerabilities/
Dec 02, 2008

I. BACKGROUND

The Sun Java JRE is Sun's implementation of the Java runtime. For more
information, see the vendor's site found at the following link.

http://www.java.com

II. DESCRIPTION

Remote exploitation of a heap overflow vulnerability in Sun Microsystems
Inc.'s Java JRE could allow an attacker to execute arbitrary code with
the privileges of the current user.

The vulnerability exists within the font parsing code in the JRE.
Various types of fonts are supported, one of which is the TrueType
format font. The vulnerability occurs when processing TrueType font
files. During parsing, improper bounds checking is performed, which can
lead to a heap based buffer overflow.

III. ANALYSIS

Exploitation allows attackers to execute arbitrary code in the context
of the currently logged-on user. To exploit this vulnerability, a
targeted user must load a malicious Web page created by an attacker. An
attacker typically accomplishes this via social engineering or injecting
content into compromised, trusted sites.

The content of the overflow buffer undergoes a series of transformations
during the font decoding process. The data is not entirely controlled by
the attacker, but there is likely enough control to allow for the
overwriting of critical data structures in a manner that makes
exploitation possible.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in Sun
Microsystem Inc.'s Java JRE version 1.6.0_07 for Windows. Previous
versions and versions for other platforms may also be affected.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this vulnerability.

VI. VENDOR RESPONSE

Sun Microsystem Inc. has released a patch which addresses this issue.
For more information, consult their advisories at the following URL.

http://onesearch.sun.com/onesearch/index.jsp?qt=Bug%206751322&charset=UTF-8

VII. CVE INFORMATION

A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not
been assigned yet.

VIII. DISCLOSURE TIMELINE

09/10/2008  Initial Vendor Notification
10/28/2008  Initial Vendor Reply
11/25/2008  Additional Vendor Feedback
12/02/2008  Coordinated Public Disclosure

IX. CREDIT

This vulnerability was discovered by Sean Larsson, iDefense Labs.

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http://labs.idefense.com/

X. LEGAL NOTICES

Copyright © 2008 iDefense, Inc.

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDefense. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically,
please e-mail customerservice@xxxxxxxxxxxx for permission.

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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