iDefense Security Advisory 11.04.08: Adobe Reader Embedded Font Handling Out of Bounds Array Indexing Vulnerability
iDefense Security Advisory 11.04.08
http://labs.idefense.com/intelligence/vulnerabilities/
Nov 04, 2008
I. 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/
II. 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.
III. 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.
IV. DETECTION
iDefense has confirmed the existence of this vulnerability in Adobe
Reader version 8.1.1. Previous versions may also be affected.
V. 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.
VI. 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
VII. 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.
VIII. 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
IX. CREDIT
This vulnerability was discovered by to Greg MacManus of iDefense Labs.
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X. LEGAL NOTICES
Copyright © 2008 iDefense, Inc.
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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.