IE 5.01 vulnerabilities in external.NavigateAndFind()

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 5.01 under Windows 95 and 5.0 under WinNT 4.0 (suppose other versions are also vulnerable) allows circumventing "Cross frame security policy" by using external.NavigateAndFind().
This exposes the whole DOM of the target document.
This allows reading local text and HTML files and files from any host (suppose reading files of any type is possible),
getting cookies (that is dangerous because may get passwords, CC #s, etc.) and other sensitive information.
It is also possible in some cases to read files behind firewall.
This vulnerability may be exploited using HTML email message or a newsgroup posting.

Details:

window.external.NavigateAndFind() is used to search for strings in specified URLs displaying the result in a specified frame.
The problem is it allows searching in "javascript:" URLs in a specified frame.
In this case the code in the "javascript:" URL is executed in the security context of the target frame and the code has access to the document loaded in the target frame.
Examine the code below for more information.

The code is:
----------------------------------------------------------------------------------------
<IFRAME NAME="I1" SRC="file://c:/test.txt"></IFRAME>
<SCRIPT>
function f()
{
window.external.NavigateAndFind("javascript:alert(document.body.innerText);","ll","I1");
}
setTimeout("f()",2000);
</SCRIPT>
----------------------------------------------------------------------------------------

Workaround:
Disable Active Scripting

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