SPS Advisory #47

RealONE Player Gold / RealJukebox2 skin file download vulnerability

UNYUN <[EMAIL PROTECTED]>
Shadow Penguin Security (http://www.shadowpenguin.org)

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*Date

July. 12, 2002

*vulnerable

RealONE Player Gold Ver. 6.0.10.505
RealJukebox2 Ver. 1.0.2.379
RealJukebox2 Ver. 1.0.2.340
RealJukebox2 Plus Ver. 1.0.2.379
RealJukebox2 Plus Ver. 1.0.2.340

*Overview

 RealJukebox2 and RealONE Player Gold can be changed the visual
appearance of application by skin file. The skin file (file extension is
"rjs") is the zip-file that contains the images and setting files. The
"skin.ini" file which is included in the zipped skin file is extracted
to known directory when skin file is loaded. If HTML tag is written in
skin.ini file, Internet Explorer regards skin.ini file as a HTML file.
In consequence, the script written in skin.ini file is executed on "My
Computer" security zone of Internet Explorer.

*Risk

 There is a possibility that the arbitrary command is executed, etc, if
the webpage that malicious HTML tag is written is browsed by Internet
Explorer or e-mail client applications that use Internet Explorer
components such as Outlook Express.

*Details

 We describe the reproduction process of this problem on Windows2000
Professional SP2+RealJukebox2 Ver. 1.0.2.340.
 First, make the following skin.ini file that contains HTML tag to
launch "c:\winnt\notepad.exe".

[skin.ini]

<html>
<OBJECT CLASSID='CLSID:15589FA1-C456-11CE-BF01-00AA0055595A'
CODEBASE='file://c:\winnt\notepad.exe'></OBJECT>
</html>

 Compress this skin.ini file by Zip utility, rename file extension from
"zip" to "rjs".

 Second, make the following HTML file (test.html), put it on webserver
together with previous made "rjs" file (exploit.rjs).

[test.html]

<html>
<META HTTP-EQUIV="Refresh" CONTENT="20;URL=file://c:\Program
Files\Real\RealJukebox\temp\~rjbtemp0\skin.ini">
<iframe src="exploit.rjs">
</html>

 Finally, browse test.html by Internet Explorer. exploit.rjs is loaded
into RealJukebox2 when test.html is browsed, the skin.ini file is
extracted. When RealJukebox2 extracts the skin file, RealJukebox2 makes
"~rjbtemp?" directory on "temp" directory which is placed on the install
directory of RealJukebox2. '?' of "~rjbtemp?" is the sequence number,
but, this value is '0' if RealJukebox2 is not launched now and
RealJukebox2 has never terminated abnormally.
 skin.ini file is extracted "~rjbtemp?" directory, test.html refers it
after 20 second. 

*Avoidance

 Information about the avoidance of this problem is published on the
webpage of RealNetworks, Inc.

 http://service.real.com/help/faq/security/bufferoverrun07092002.html

*Caution

 We will change this information without any notice. Use of this
information constitutes acceptance for use in an AS IS condition. There
are NO warranties with regard to this information. In no event shall the
author be liable for any damages whatever arising out of or in
connection with the use or spread of this information. Any use of this
information is only for personal experiment.

*Comments ?

If you have something comments, please send to following address.
webmaster <[EMAIL PROTECTED]>
http://www.shadowpenguin.org

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