iDefense Security Advisory 06.10.08: Multiple Vendor FreeType2 PFB Memory Corruption Vulnerability

2008-06-10T00:00:00
ID SECURITYVULNS:DOC:20009
Type securityvulns
Reporter Securityvulns
Modified 2008-06-10T00:00:00

Description

iDefense Security Advisory 06.10.08 http://labs.idefense.com/intelligence/vulnerabilities/ Jun 10, 2008

I. BACKGROUND

FreeType2 is an open source library for parsing fonts that is used by many applications. This includes projects such as X.Org, Second Life, and the Sun Java JRE. For more information, please see the vendor's website at the following URL.

http://freetype.sourceforge.net/freetype2/

II. DESCRIPTION

Remote exploitation of a memory corruption vulnerability in the FreeType2 library, as included in various vendors' operating systems, could allow an attacker to execute arbitrary code with the privileges of the affected application.

The vulnerability exists within the code responsible for parsing Printer Font Binary (PFB) format font files. By providing an invalid 'number of axes' in the file, it is possible to cause the code to call the free() function on areas of memory that were not dynamically allocated. This can lead to memory corruption, which can allow for the execution of arbitrary code.

III. ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the application using the library. Since FreeType2 is a library and not a standalone application, the exploitation vector will vary. iDefense Labs verified that local privilege escalation was possible via the X.Org Xserver.

IV. DETECTION

iDefense has confirmed the existence of this vulnerability in FreeType2 version 2.3.5. Previous versions may also be affected.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue. Changing the permissions on the freetype.so library may not always be effective since applications that run with root privileges are not restricted by file permissions.

VI. VENDOR RESPONSE

The FreeType maintainers addressed this vulnerability with the release of version 2.3.6. For more information, refer to the release notes at the following URL.

http://sourceforge.net/project/shownotes.php?group_id=3157&release_id=605780

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2008-1807 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

06/03/2008 Initial vendor notification 06/04/2008 Initial vendor response 06/10/2008 Coordinated public disclosure

IX. CREDIT

This vulnerability was reported to iDefense by regenrecht.

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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.