RealPlayer Zipped Skin File Buffer Overflow

Release Date:
October 27, 2004

Date Reported:
October 11, 2004

Severity:
High (Code Execution)

Vendor:
RealNetworks

Systems Affected:
For Microsoft Windows
RealPlayer 10.5 (6.0.12.1053 and earlier)
RealPlayer 10
RealOne Player v2
RealOne Player v1

Overview:
eEye Digital Security has discovered a vulnerability in RealPlayer that
allows a remote attacker to reliably overwrite the stack with arbitrary
data and execute arbitrary code in the context of the user under which
the player is running.

Technical Details:
A RealPlayer skin file (.rjs extension) can be downloaded and applied
automatically through a web browser without the user's permission. A
skin file is a bundle of graphics and a .ini file, stored together in
ZIP format. DUNZIP32.DLL, which is included with RealPlayer, is used to
extract the contents of the skin file. When an .rjs file containing a
long file name (greater than around 0x8000 bytes) is opened, either in
RealPlayer or through a web browser, a stack based buffer overflow
occurs, allowing an exception handler record to be overwritten and EIP
to be hijacked.

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. "Security Update - Skin File Overflow" Recommended
Player Update: Resolves a security vulnerability when activating a
specifically malformed skins file. Skins files available on RealNetworks
site are examined before being posted. Skins files from other sources
should be treated with caution. 

Credit:
Discovery: Yuji Ukai

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

Greetings:
TCC, YY, KEN, O.C., Guys@Shinbashi_Sanuki-Iyo_Place,
Guys@NightLandSlotmachinePlayroom

Copyright (c) 1998-2004 eEye Digital Security
Permission is hereby granted for the redistribution of this alert
electronically. It is not to be edited in any way without express
consent of eEye. If you wish to reprint the whole or any part of this
alert in any other medium excluding electronic medium, please email
alert@eEye.com for permission.

Disclaimer
The information within this paper may change without notice. Use of this
information constitutes acceptance for use in an AS IS condition. There
are no warranties, implied or express, with regard to this information.
In no event shall the author be liable for any direct or indirect
damages whatsoever arising out of or in connection with the use or
spread of this information. Any use of this information is at the user's
own risk.