*** Windows Media Player Plugin: Local File Detection Vulnerability***
A design flaw in Windows Media Player 11 allows a remote attacker to determine the presence of local files (programs,
documents, etc.). I sent an e-mail to Microsoft (nearly a year ago) but they never responded…
Windows Media Player permits to open locally stored media-files. Opening non-supported files usually provokes an error
message. By a simple HTTP-redirect, the error message can be circumvented. Local files can be opened. The
file-opening-procedure can be controlled with the “Player.OpenStateChange Event”. If a file exists, event 8
(”MediaChanging”) is fired. This way, via JavaScript, a malicious web site could determine the presence of local (and
remote) files.
Additional infos (in German): www.lrv.ch.vu
I’ve also set up a demo page at: http://lrv.bplaced.net/wmp/wmp.php