Media Player Security Vulnerabilities

Microsoft has released a patch that eliminates two security vulnerabilities in Microsoft Windows Media Player. These vulnerabilities could potentially enable a malicious user to cause a program of his choice to run on another user's computer.

The two vulnerabilities discussed below are unrelated to each other except by the fact that they both affect Windows Media Player. We packaged them in a single patch to make it more convenient for customers to apply. The vulnerabilities are:
The ".ASX Buffer Overrun" vulnerability. Windows Media Player supports the use of Active Stream Redirector (.ASX) files to enable users to play streaming media that resides on intranet or Internet sites. However, the code that parses .ASX files has an unchecked buffer, and this could potentially enable a malicious user to run code of his choice on the machine of another user. The malicious user could either send an affected file to another user and entice her to run or preview it, or he could host such a file on a web site and cause it to launch automatically whenever a user visited the site. The code could take any action on the machine that the legitimate user herself could take.
The ".WMS Script Execution" vulnerability. Windows Media Player 7 introduced a feature called "skins", that allows customization of the look and feel of Windows Media Player. However, a custom skin (.WMS) file could potentially include script, which would execute if Windows Media Player was run and that skin was selected. A malicious user could either send a customized skin containing script to another user and try to entice her into using it, or he could host such a file on a web site and cause it to launch automatically whenever a user visited the site. Because the code would reside on the user's local machine, it would be able to execute ActiveX controls, including ones not marked "safe for scripting". This would enable the code to take any action that can be accomplished via an ActiveX control.