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Adobe Reader 6.0 .ETD File Format String Vulnerability

12.14.04

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/acrobat/readermain.html

DESCRIPTION

Remote exploitation of a format string vulnerability in version 6.0.2
of Adobe's Reader could allow attackers to execute arbitrary code.

The problem specifically exists in the parsing of .etd files used in
eBook transactions. A .etd file containing a format string in the
'title' or 'baseurl' fields can cause an invalid memory access:

<title>|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|</title>
<baseurl>|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|%p|</baseurl>

This may allow for the execution of arbitrary code.

ANALYSIS

Successful exploitation allows an attacker to execute arbitrary code
under the privileges of the local user. Remote exploitation is possible
by sending a specially crafted e-mail and attaching either the
maliciously crafted PDF document or a link to it.

DETECTION

iDEFENSE has confirmed that Adobe Reader version 6.0.2 is vulnerable.
It is suspected that earlier versions of Adobe Reader 6 are also
vulnerable. Adobe Acrobat may also be vulnerable.

WORKAROUND

Deleting the following file will prevent exploitation of this
vulnerability:

"C:Program FilesAdobeAcrobat 6.0Readerplug_inseBook.api"

This will not impact reading .PDF files.

Removing this file prevents Adobe Reader from handling eBooks. When a
file handled by this plugin is detected, an error dialog box will
appear, offering to take the user to Adobe's website for information.

VENDOR RESPONSE

This vulnerability is addressed in Adobe Acrobat Reader 6.0.3. Downloads
for platform specific versions are available at the links shown below:

Reader/Win:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2679

Reader/Mac:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2680

Acrobat/Win:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2677

Acrobat/Mac:
http://www.adobe.com/support/downloads/detail.jsp?ftpID=2676

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
names CAN-2004-1153 to these issues. This is a candidate for inclusion
in the CVE list (http://cve.mitre.org), which standardizes names for
security problems.

DISCLOSURE TIMELINE

10/13/2004   Initial vendor notification
10/14/2004   Initial vendor response
12/14/2004   Coordinated public disclosure

CREDIT

This vulnerability was discovered by Greg MacManus, iDEFENSE Labs.

Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp

LEGAL NOTICES

Copyright © 2004 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
email 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.