Secunia

Secunia Research has discovered a vulnerability in Mozilla and Mozilla Firefox, which can be exploited by malicious people to trick users into downloading malicious files.

The problem is that the browser uses the URL to determine the file type association in the "Save Link As" download dialog, but uses the filename from the "Content-Disposition" HTTP header when saving the downloaded file. This can be exploited by a malicious web site to spoof file types in the "Save Link As" download dialog.

Successful exploitation can lead to malware being saved to the download directory (default is the desktop on Mozilla Firefox).

NOTE: Exploitation requires that the option "Hide extension for known file types" is enabled in Windows (default setting).

The vulnerability has been confirmed in Mozilla 1.7.3 and Mozilla Firefox 1.0 for Windows. Other versions may also be affected.

Solution
The vendor has issued updated versions.
Further details available in Customer Area

Provided and/or discovered by
Andreas Sandblad, Secunia Research.

Changelog
Further details available in Customer Area

Original Advisory
Secunia Research:
http://secunia.com/secunia_research/2004-21/advisory/

Mozilla:
http://www.mozilla.org/security/announce/mfsa2005-22.html

Deep Links
Links available in Customer Area