Public Vulnerability Reports

Adobe Reader Embedded Font Handling Out of Bounds Array Indexing Vulnerability

11.04.08

BACKGROUND

Adobe Acrobat Reader is a program for viewing Portable Document Format (PDF) documents. More information is available at the following site:

http://www.adobe.com/products/reader/

DESCRIPTION

Remote exploitation of an out of bounds array access vulnerability in Adobe System Inc.'s Adobe Reader could allow an attacker to execute arbitrary code as the current user.

The vulnerability specifically exists in code responsible for parsing Type 1 fonts. After allocating an area of memory, no bounds checking is performed. Subsequent access of this memory may result in modification of arbitrary memory, which in turn may result in arbitrary code execution.

ANALYSIS

Exploitation of this vulnerability would allow a remote attacker to execute arbitrary code as the current user. In order to exploit this vulnerability, the attacker would have to convince the target user to open a maliciously crafted file, either by opening an email attachment or visiting a website which contained an embedded PDF file. No further interaction is required. The Explorer extension which displays the thumbnail view of the document, AcroRd32Info, is also vulnerable. This may allow the vulnerability to be exploited by simply clicking on a PDF file without opening it, even from a network share.

DETECTION

iDefense has confirmed the existence of this vulnerability in Adobe Reader version 8.1.1. Previous versions may also be affected.

WORKAROUND

iDefense is currently unaware of any effective workarounds for this issue.

Configuring the application not to open in the browser may mitigate exposure to some web-based attacks.

VENDOR RESPONSE

Adobe has released a patch which addresses this issue. For more information, consult their advisory at the following URL.

http://www.adobe.com/support/security/bulletins/apsb08-19.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2008-4812 to this issue. This is a candidate for inclusion in the CVE list (http://cve.mitre.org/), which standardizes names for security problems.

DISCLOSURE TIMELINE

12/27/2007 Initial Vendor Notification
12/28/2007 Initial Vendor Reply
10/31/2008 Additional Vendor Feedback
11/04/2008 Coordinated Public Disclosure

CREDIT

This vulnerability was discovered by to Greg MacManus of iDefense Labs.

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LEGAL NOTICES

Copyright © 2008 Verisign, 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 customer service 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.