Vulnerability Note VU#928689

SunnComm MediaMax privilege elevation vulnerability

SunnComm MediaMax is copy protection software that is automatically installed by some audio CDs. Sony BMG has provided a list of titles that include MediaMax version 5 software. A device driver is Included with the MediaMax software, which prevents the CD from being copied. The user must be a member of the Windows "Administrators" or "Power Users" group for the software to install. Note that the driver and part of the software is installed before the End User License Agreement (EULA) is presented to the user.

The problem

The MediaMax software is installed with file permissions that are not restrictive enough. The MediaMax software is located in "\Program Files\Common Files\SunnComm Shared." The MediaMax installer grants "Full Control" file permissions to "Everyone," which means that any user of the system may replace the MediaMax software with arbitrary code. The next time a CD that contains MediaMax is launched, this code will run with the privileges of the user that is logged on. If the user who launches the MediaMax CD has administrative privileges, then the attacker-supplied code will also run with administrative privileges.

II. Impact

SunnComm has provided a Frequently Asked Questions document and an update to address this issue.

Disable Autorun

To help protect yourself against software running without your consent, disable Autorun as described in Microsoft Support Document 155217. This will prevent Windows from automatically running software when CD or DVD media is inserted.

Use least privilege

Use "least privilege" approach to user accounts. By reducing the privileges of the user accounts, the impact of this and other vulnerabilties may be reduced. More information about this technique is available in the Microsoft TechNet article Applying the Principle of Least Privilege to User Accounts on Windows XP.

Systems Affected

http://www.sunncomm.com/support/faq/
http://www.sonybmg.com/mediamax/titles.html
http://www.eff.org/IP/DRM/Sony-BMG/MediaMaxVulnerabilityReport.pdf
http://www.eff.org/news/archives/2005_12.php#004234
http://www.securityfocus.com/bid/15754
http://securitytracker.com/id?1015327
http://secunia.com/advisories/17933

Credit

Thanks to EFF for reporting this vulnerability, who in turn credit Jesse Burns and Alex Stamos of iSEC Partners.

This document was written by Will Dormann.

Other Information

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