iDefense Security Advisory 06.14.11: Adobe Shockwave Lingo Script Opcodes Integer Signedness Vulnerability

iDefense Security Advisory 06.14.11
http://labs.idefense.com/intelligence/vulnerabilities/
Jun 14, 2011

I. BACKGROUND

Adobe Shockwave Player is a popular Web browser plug-in. It is available
for multiple Web browsers and platforms, including Windows, and MacOS.
Shockwave Player enables Web browsers to display rich multimedia content
in the form of Shockwave videos. For more information, see the vendor's
site found at the following link:

http://get.adobe.com/shockwave

II. DESCRIPTION

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

This vulnerability occurs when Shockwave processes a maliciously
constructed "Lscr" record. This record can embed Lingo script code,
which is Shockwave's scripting language. The vulnerability occurs when
processing certain opcodes. Specifically, a 32-bit value from the file
is used as an offset into a heap buffer without proper validation. When
comparing the value to the maximum buffer size, a signed comparison is
performed. By using a negative value, it is possible to index outside of
the allocated buffer. This results in data outside of the buffer being
treated as a valid pointer, and this pointer is later used as the
destination of a write operation. This can corrupt an arbitrary memory
address, which can lead to the execution of arbitrary code.

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

Shockwave Player version 11.5.9.620 and prior are vulnerable.

V. WORKAROUND

iDefense is currently unaware of any workarounds for this issue.

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/apsb11-17.html

VII. CVE INFORMATION

The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CVE-2011-0335 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

05/18/2011 Initial Vendor Notification
05/18/2011 Initial Vendor Reply
06/14/2011 Coordinated Public Disclosure

IX. CREDIT

This vulnerability was reported to iDefense by Luigi Auriemma.

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X. LEGAL NOTICES

Copyright © 2011 Verisign

Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
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e-mail [email protected] 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.