iDefense Security Advisory 11.04.08 http://labs.idefense.com/intelligence/vulnerabilities/ Nov 04, 2008 I. BACKGROUND Adobe Reader is a program for viewing Portable Document Format (PDF) documents. Acrobat is the program used to create such documents. More information is available at the following URLs. http://www.adobe.com/products/acrobat/ http://www.adobe.com/products/reader/ II. DESCRIPTION Remote exploitation of a heap corruption vulnerability in Adobe Systems Inc.'s Acrobat Professional and Reader could allow an attacker to execute arbitrary code with the privileges of the current user. The vulnerable code is an AcroJS function available to scripting code inside of a PDF document. This function is used for HTTP authentication. By passing a long string to this function, it is possible to corrupt heap memory in such a way that may lead to the execution of arbitrary code. III. ANALYSIS Exploitation of this vulnerability would allow an attacker to execute arbitrary code with the privileges of the current user. In order to exploit this vulnerability, an attacker would have to convince the target to open a maliciously constructed file, or to visit a website with an embedded PDF. If the user has the Adobe Reader Browser plugin enabled, the PDF file will render inside of the browser. IV. DETECTION iDefense has confirmed the existence of this vulnerability in Acrobat Professional and Adobe Reader version 8.1.2. Previous versions may also be affected. V. WORKAROUND Disabling JavaScript in Adobe Reader or Acrobat will limit exposure to this vulnerability. When JavaScript is disabled, Adobe Reader will prompt the user that some components of the document may not function, and provide an opportunity to enable it. VI. VENDOR RESPONSE Adobe reports that the input validation issue in the Download Manager used by Adobe Reader has been resolved and has released a patch which addresses this issue. A patch is available from the vendor at: 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-2008-4817 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 03/21/2008 Initial Vendor Notification 04/28/2008 Additional iDefense Data Provided to Vendor 06/26/2008 Additional Vendor Follow-up 11/04/2008 Coordinated Public Disclosure IX. CREDIT This vulnerability was reported to iDefense by an anonymous contributor. 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. _______________________________________________ Full-Disclosure - We believe in it. Charter: http://lists.grok.org.uk/full-disclosure-charter.html Hosted and sponsored by Secunia - http://secunia.com/