-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 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. II. DESCRIPTION Remote exploitation of an integer 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. As part of its font API, the JRE provides the ability to load a font from a remote URL. Various types of fonts are supported, one of which is the TrueType format font. The vulnerability occurs when parsing various structures in TrueType font files. During parsing, values are taken from the file, and without being properly validated, used in operations that calculate the number of bytes to allocate for heap buffers. The calculations can overflow, resulting in a potentially exploitable heap 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. IV. DETECTION iDefense has confirmed the existence of this vulnerability in Sun Microsystem Inc.'s Java JRE version 1.6.0_05 for Windows. Previous versions may also be affected. V. WORKAROUND There is a potential workaround for the vulnerability, but it renders the JRE unusable. It is possible to use the cacls program to change the file permissions on fontmanager.dll. This will prevent the vulnerable library from loading. However, this workaround has a serious impact on the functionality of the JRE. When a webpage attempts to load an applet, the JRE will abort with a runtime error, and the browser will close. VI. VENDOR RESPONSE Sun Microsystem Inc. has released a patch which addresses this issue. For more information, consult their advisory at the following URL. http://sunsolve.sun.com/search/document.do?assetkey=1-66-244987-1 VII. CVE INFORMATION A Mitre Corp. Common Vulnerabilities and Exposures (CVE) number has not been assigned yet. VIII. DISCLOSURE TIMELINE 07/31/2008 Initial Vendor Notification 08/01/2008 Initial Vendor Reply 10/21/2008 Additional Vendor Feedback 11/26/2008 Additional Vendor Feedback 12/02/2008 Coordinated Public Disclosure IX. CREDIT This vulnerability was reported to iDefense by Sebastian Apelt (webmaster@buzzworld.org). Get paid for vulnerability research http://labs.idefense.com/methodology/vulnerability/vcp.php Free tools, research and upcoming events 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@idefense.com 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. -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.7 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJOFsZbjs6HoxIfBkRAkAXAKCustwzLXcOKMcDJ1sZ0GonmW4F8ACg6Dva mqtkKX2/C9fA7aiyNDRtgbA= =Oo+F -----END PGP SIGNATURE-----