Automatic MIME type detection in Internet Explorer 6.x allowed

[email protected]
Newsgroups gmane.comp.security.vulnerabilities
Message-ID <[email protected]>
Automatic MIME type detection in Internet Explorer 6.x allowed 
downloading executable file automatically

+Background:
  What's Internet Explorer automatic MIME type detection?
 - This feature was included in IE to detect exactly MIME type from 
file on server sending to browser
 by using FindMimeFromData method.

+Description:
-  I've found out that using Automatic MIME type detection, we can 
force IE to download any file 
(including excutable file) without user's knowledge by causing IE treat 
executable file as a image (jpg,gif..). 
Thus, IE automatically download the file regardless of the file type,  
and save it in "Temporary Internet Files" folder when user visit 
attacker's website.

+Exploitation:
   - Force user to download any executable files:
          _  Create a file named "app.exe" with  a head body contained 
any jpg file content
	to force IE MIME type detection recognize it as a image file.
          _   When user browse the website which contained the file 
we've just created.
	IE simply treat it as a image so it automatically save that file in 
Temporary folder.
         * This exploit can be found here:
	Open this link: http://sendmailplus.com/knight4vn/app1.exe
	Open this 
link: http://sendmailplus.com/knight4vn/app2.exe
	After that, check the 
appearance of "app1.exe" "app2.exe" in your "Temporary internet 
folder".
    - IE treat malicious javascript as a image:
        * This exploit can be found here:
	http://www.sendmailplus.com/knight4vn/js.gif
	
http://www.sendmailplus.com/knight4vn/js.jpg
	
http://www.sendmailplus.com/knight4vn/js.png

Discovered by: Knight Commander ([email protected], 
[email protected])
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