[37624] in bugtraq
IE6 Vulnerability - Local File Detection
daemon@ATHENA.MIT.EDU (ViPeR)
Tue Dec 7 20:44:36 2004
Message-ID: <20041207121935.64241.qmail@web8510.mail.in.yahoo.com>
Date: Tue, 7 Dec 2004 12:19:35 +0000 (GMT)
From: ViPeR <viper31337@yahoo.co.in>
To: bugtraq@securityfocus.com
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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)
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