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Adobe Flash Player ActionScript Integer Overflow Vulnerability

08.02.11

BACKGROUND

Adobe Flash Player is an application for viewing animations and movies using computer programs such as a Web browser; in common usage, Flash lets you put animation and movies on a website. Flash Player runs SWF files that can be created by the Adobe Flash authoring tool, by Adobe Flex or by a number of other Macromedia and third party tools. For more information, please visit following website:

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

DESCRIPTION

Remote exploitation of an integer overflow vulnerability in Adobe Systems Inc.'s Flash Player could allow an attacker to execute arbitrary code with the privileges of the current user.

The vulnerability occurs when parsing a maliciously formatted sequence of ActionScript code inside an Adobe Flash file. The problem exists in the ActionScript method of the built-in "Function" class, which accepts an array object as a second parameter and uses this array's length multiplied by four for a memory allocation without any overflow checks. Then it writes the array's content into the allocated memory, which corrupts memory and leads to an exploitable condition.

ANALYSIS

Exploitation of this vulnerability results in the execution of arbitrary code with the privileges of the user viewing the Web page. To exploit this vulnerability, a targeted user must load a malicious Web page created by an attacker. An attacker typically accomplishes this via social engineering or injecting content into compromised, trusted sites. After the user visits the malicious Web page, no further user interaction is needed.

DETECTION

iDefense has confirmed the existence of this vulnerability in the Flash Plugin version 10.1.82.76 and 10.1.85.3. A full list of vulnerable Adobe products can be found in Adobe Security Bulletin APSB11-02.

WORKAROUND

Disable Flash Player plugin by restricting access to Flash Player files, which are usually under C:WINDOWSsystem32MacromedFlash folder

VENDOR RESPONSE

Adobe has addressed this issue with an update. Further details and patches can be found at the following URL.

http://www.adobe.com/support/security/bulletins/apsb11-02.html

CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the name CVE-2011-0558 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

09/22/2010 Initial Vendor Notification
09/22/2010 Initial Vendor Reply
02/08/2011 Coordinated Public Disclosure

CREDIT

This vulnerability was reported to iDefense by Vitaliy Toropov.

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LEGAL NOTICES

Copyright © 2011 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.