Reporter Gregory R. Panakkal
`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
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
There isn't much of a documentation on the net
regarding the "sysimage://", atleast google didn't
show up anything useful :(
Proof Of Concept
onLoad="document.write('<b>Cannot Find File!</b>');"
A demonstration is available at the following URL.
Liu Die Yu, Rakesh Balasunder
Gregory R. Panakkal
(aka JunkCode / Viper)