An ActiveX control included with Windows Media Player 9 Series allows Web page authors to create Web pages that can play media and provide a user interface by which the user can control playback. When a user visits a Web page with embedded media, the ActiveX control provides a user interface that allows the user to take such actions as pausing or rewinding the media.

A flaw exists in the way in which the ActiveX control provides access to information on the user's computer. A vulnerability exists because an attacker could invoke the ActiveX control from script code, which would allow the attacker to view and manipulate metadata contained in the media library on the user's computer.

Microsoft Windows Media Services is a feature of Microsoft Windows 2000 Server, Advanced Server, and Datacenter Server and is also available in a downloadable version for Windows NT 4.0 Server. Windows Media Services contains support for a method of delivering media content to clients across a network known as multicast streaming. In multicast streaming, the server has no connection to or knowledge of the clients that may be receiving the stream of
media content coming from the server. To facilitate logging of client information for the server, Windows 2000 includes a capability specifically designed to enable logging for multicast transmissions.