Re: IE6 Vulnerability - Local File Detection

[RSnake <rsnake () shocking com>]

        This may be obvious, but using this proof of concept you can see
        how it can be used to do remote OS detection as well as
        vulnerability detection (seems bad).  You need IE with JS
        on to view the demo:

        http://www.shocking.com/~rsnake/detect.html

On Tue, 7 Dec 2004, ViPeR wrote:

| Date: Tue, 7 Dec 2004 12:19:35 +0000 (GMT)
| From: ViPeR <viper31337 () yahoo co in>
| To: bugtraq () securityfocus com
| Subject: IE6 Vulnerability - Local File Detection
| 
| Affected Software : Microsoft Internet Explorer
| Vulnerability : Local File Detection
| 
| Tested On : MS IE 6.0 SP1, Win2K SP4, [up-to-date]
| according to windowsupdate.com
| 
| Discovered by : Gregory R. Panakkal
| 
| 
| Overview
| ========
| This security vulnerability in Internet Explorer
| allows remote attackers to discover what software is
| installed on the remote computer, by testing for the
| existence of certain files. 
| 
| The "sysimage://" protocol is used to display the
| appropriate icon corresponding to a  file path when
| viewed from MSIE. The default behaviour is such, that
| if a existing file-path is given as input, it displays
| the approritate icon [as described above], but if the
| file-path supplied doesn't exists, it loads the icon
| of a folder instead [ie, it gives out no error].
| 
| But as always, there is a way to bypass it.. and let
| us differentiate between a valid path and an invalid
| one, and thus using the onLoad and onError event
| handlers, the 'local file detection' is a piece of
| cake.
| 
| There isn't much of a documentation on the net
| regarding the "sysimage://", atleast google didn't
| show up anything useful :(
| 
| 
| 
| Proof Of Concept
| ================
| 
| <img src="sysimage://C:\WINNT\Notepad.exe,666"
| onLoad="document.write('<b>Cannot Find File!</b>');"
| onError="document.write('<b>File Exists!</b>');">
| 
| 
| Demo
| ====
| 
| A demonstration is available at the following URL.
| 
| http://crapware.lx.ro/junkcode/security/ie-sp1-sysimage-local-file-existence.htm
| 
| 
| Greetz to
| =========
| Liu Die Yu, Rakesh Balasunder
| 
| 
| rgds,
| Gregory R. Panakkal 
| (aka JunkCode / Viper)
| 
| ________________________________________________________________________
| Yahoo! India Matrimony: Find your life partner online
| Go to: http://yahoo.shaadi.com/india-matrimony
| 

-R

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