Georgi Guninski security advisory #12, 2000

IE 5 Cross-frame security vulnerability using IFRAME and WebBrowser control

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Internet Explorer 5.01 under Windows 98 (suppose all other versions are also vulnerable) allows circumventing "Cross frame security policy" by accessing the DOM of documents using JavaScript, IFRAME and WebBrowser control.
This exposes the whole DOM of the target document and opens lots of security risks.
This allows reading local files, reading files from any host, window spoofing, getting cookies, etc.


IFRAME seems to be some kind of wrapper of the WebBrowser control and its events may be captured.
The problem is the NavigateComplete2 event, which when fired, passes an argument of WebBrowser control.
The WebBrowser control has an accessible property "document" that allows access to the DOM of the target document.

Note: this is a similar vulnerability to the one discovered by Andrew Nosenko (which is already fixed): (could not find a better link)

The code is:
<SCRIPT for=I1 event="NavigateComplete2(b)">
alert("Here is your file:\n"+b.document.body.innerText);

Demonstration is available at:

Workaround: Disable Active Scripting

Copyright 2000 Georgi Guninski

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