Internet Explorer 6 Download Spoof Vulnerability

Secunia has issued a ‘Moderately critical’ advisory following the discovery of a fresh download spoofing vulnerability in Internet Explorer (prior versions may also be affected). The solution is to always Save files to a folder - and not use ‘Open’ file - as this reveals the suspicious filename:

http-equiv has identified a vulnerability in Internet Explorer, allowing malicious web sites to spoof the file extension of downloadable files. The problem is that Internet Explorer can be tricked into opening a file, with a different application than indicated by the file extension. This can be done by embedding a CLSID in the file name. This could be exploited to trick users into opening "trusted" file types which are in fact malicious files.

Secunia has created an online test:
http://secunia.com/Internet_Explorer_File_Download_Extension_Spoofing_Test/

Secunia
Internet Explorer File Download Extension Spoofing