I. BACKGROUND
RealPlayer is an application for playing various media formats,
developed by RealNetworks Inc. For more information, visit
http://www.real.com/
II. DESCRIPTION
Remote exploitation of a buffer overflow in Version 10 of Real Networks'
RealPlayer could allow execution of arbitrary commands.
The vulnerability specifically exists in the handling of URLs with a
large number of period (".") characters. By creating a specially crafted
filename, it is possible to cause the execution of arbitrary code with
the permissions of the user that attempts to access it.
III. ANALYSIS
One method of exploiting this vulnerability is to place a .RAM file
(RealPlayer Presentation) containing a maliciously constructed URL on a
web server and send an e-mail to the target with a link containing the
file.
It appears the vulnerability results from allocating an array of a fixed
size and then iterating through the URL looking for periods. As each one
is found, a pointer to it is stored in the array, and the current index
is incremented. No check seems to be done for writes to addresses
outside the array.
IV. DETECTION
RealNetworks' RealPlayer 10 is confirmed vulnerable. Previous versions
of RealPlayer are also suspected to be vulnerable.
V. WORKAROUND
iDEFENSE is currently unaware of any effective workarounds for this
vulnerability.
User awareness is the best defense against this class of attack. Users
should be aware of the existence of such attacks and proceed with
caution when following links from suspicious and/or unsolicited e-mail.
VI. VENDOR RESPONSE
Real Networks recommends updating affected applications to the latest
version. Instructions for upgrading are contained in the vendor's
security advisory located at:
http://service.real.com/help/faq/security/040610_player/EN/
VII. CVE INFORMATION
The Common Vulnerabilities and Exposures (CVE) project has assigned the
name CAN-2004-0550 to this issue. This is a candidate for inclusion in
the CVE list (http://cve.mitre.org), which standardizes names for
security problems.
VIII. DISCLOSURE TIMELINE
04/14/2004 Exploit discovered by iDEFENSE
05/12/2004 Initial vendor notification
05/12/2004 iDEFENSE clients notified
05/13/2004 Vendor response
06/10/2004 Coordinated public disclosure
IX. CREDIT
Greg MacManus (iDEFENSE Labs) is credited with this discovery.
Get paid for vulnerability research
http://www.idefense.com/poi/teams/vcp.jsp
X. LEGAL NOTICES
Copyright © 2004 iDEFENSE, Inc.
Permission is granted for the redistribution of this alert
electronically. It may not be edited in any way without the express
written consent of iDEFENSE. If you wish to reprint the whole or any
part of this alert in any other medium other than electronically, please
email customerservice@idefense.com for permission.
Disclaimer: The information in the advisory is believed to be accurate
at the time of publishing based on currently available information. Use
of the information constitutes acceptance for use in an AS IS condition.
There are no warranties with regard to this information. Neither the
author nor the publisher accepts any liability for any direct, indirect,
or consequential loss or damage arising from use of, or reliance on,
this information.
