RealPlayer embd3260.dll Error Response Heap Overflow

Release Date:
June 10, 2004

Date Reported:
May 14, 2004

Severity:
High (Remote Code Execution)

Vendor:
RealNetworks

Systems Affected:
RealOne Player 
RealOne Player v2
RealPlayer 10
RealPlayer 8
RealPlayer Enterprise

Description:
eEye Digital Security has discovered a critical vulnerability in
RealPlayer.  The vulnerability allows a remote attacker to reliably
overwrite heap memory with arbitrary data and execute arbitrary code in
the context of the user who executed the player or application hosting
the RealMedia plug-in.

This specific flaw exists within the embd3260.dll file used by
RealPlayer.  By specially crafting a malformed movie file along with an
HTML file, a direct heap overwrite is triggered, and reliable code
execution is then possible.

Technical Description:
The code in embd3260.dll among other things is responsible for crafting
error messages in RealPlayer.  The vulnerability is triggered by
crafting a malformed movie which is then embedded into an HTML page,
causing RealPlayer to generate a error in the form of
"mem://[address]/[movie file name]", resulting in a heap overflow.  A
heap block is allocated to contain the error message, but because of a
flaw in how the buffer size is calculated, an overflow will always
happen.  The following pseudocode represents the vulnerable condition:

char *errormessage = new char[strlen(moviename)+10];
sprintf(errormessage, "mem://%08X/", address);
strcat(errormessage, moviename); 

Protection:
Retina Network Security Scanner has been updated to identify this
vulnerability.

Vendor Status:
RealNetworks has released a patch for this vulnerability. The patch is
available via the "Check for Update" menu item under Tools on the
RealPlayer menu bar.
A link to their advisory can be found here:
http://service.real.com/help/faq/security/040610_player/EN/

Credit:
Discovery: Karl Lynn
Additional Research: Derek Soeder

Related Links:
Retina Network Security Scanner - Free 15 Day Trial
http://www.eeye.com/html/Products/Retina/download.html

Greetings:
HD Moore, Riley Hassell, K2, Bronc Buster, RSnake, Kelly H., and the
entire staff at eEye.

Copyright (c) 1998-2004 eEye Digital Security
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