Research Archives > Security Advisories > AD20040610

RealPlayer embd3260.dll Error Response Heap Overflow

Release Date:
6/10/2004 12:00:00 AM

Date Reported:
5/14/2004 12:00:00 AM

Severity:
High

Vendor:
RealNetworks

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

Overview:
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 Details:
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

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

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