Application: Firefox 3.0.11 OS: Windows XP - SP3 ------------------------------------------------------ 1 - Description 2 - Vulnerability 3 - POC/EXPLOIT ------------------------------------------------------ Description This software is a popular web browser that supports multiple platforms as (windows,linux,macos). ------------------------------------------------------ Vulnerability The bug is caused when you try to open a url with a invalid char, in this time, you can edit the error page, and make a "spoof". This not would be important because when you make the spoof the "invalid web" is loading all time, but as firefox allow that you call the "stop" method of other page you can stop this. The result of this is a fake page. ------------------------------------------------------ POC/EXPLOIT The poc is a simple script that have a window.open(), it calls the url with invalid char, the invalid char can be a "," or "%" is important that you add some "%20" for display a "white space" in the url. http://es.geocities.com/jplopezy/firefoxspoofing.html PD : I send this to bugzilla ------------------------------------------------------ Juan Pablo Lopez Yacubian