Netscape 4.x javascript security flaw Versions tested: Windows98/Netscape4.7,Windows95/Netscape4.05 Description: (Credits to Henri Torgemane) Netscape has a "persistent" navigator object, which means that any data put in the window.navigator object will be accessible to every other window as long as the browser is running. This is slightly worse than non-persistent cookies since it works across domains. (not by much.. advertisers didn't wait for this feature to track users from different sites) Any window that somehow gets an handle to another window can look at it. If you try to explore the objects inside that window, you'll see pretty much every global function and variable defined on that window. But you cannot see "sensitive" objects like document, history, location, etc.. This is mostly an attempt at not breaking compatibility with scripts developed with previous versions of Navigator: Every object can be accessed except those known to be sensitive. (Credits to Ahmed Ghandour) ex: Its not possible (un least I dont found any way yet) to access sensitive objects like document location or form, but if the window javascript code copy any of this values into a global javascript variable(which a lot of sites do) the user can gain access to this sensitive information. ex. Another way to access sensitive information is overridden some global function which receive sensitive information parameters ex. If you go to the demo page you can see the function example above in action, I did this in the Online Crestar bank home page. Solution: Turn of javascript Subject: Re: Netscape communicator 4.x Javascript security flaw Date: Fri Nov 26 1999 09:03:16 Author: Ahmed Ghandour >But you cannot use it to automatically grab form data as >was implied >on the nsSecurityFlaw1.html page. I know this but what you can do is overriden a global function like validForm(form)wich you can found in the crestar bank page with your own function and that way you can have access to his document.form object and also grab his customer number and pin code! You can do one script to automatic overriden any javascript function in any page from any domain visit by the user! And this is a big security hole! Thanks Ahmed Ghandour