iDefense Security Advisory 02.08.11: Adobe Flash Player ActionScript Integer Overflow Vulnerability

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iDefense Security Advisory 02.08.11
http://labs.idefense.com/intelligence/vulnerabilities/
Feb 08, 2011

I. 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/

II. 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.

III. 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.

IV. 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.

V. WORKAROUND

Disable Flash Player plugin by restrict access to Flash Player files,
which are usally under C:\WINDOWS\system32\Macromed\Flash\ folder

VI. 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

VII. 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.

VIII. DISCLOSURE TIMELINE

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

IX. CREDIT

This vulnerability was reported to iDefense by Vitaliy Toropov.

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X. LEGAL NOTICES

Copyright © 2011 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.
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