There is a bug in Netscape Communicator 4.51,4.5/Win95, 4.08/WinNT (probably others?), which allows sniffing URLs from another window.
This page tracks the URLs the user visits in another window.
Enter your URL in the 'Tracked window'. Wait until the document is loaded, then click 'Show URL'.
This exploit needs Javascript enabled.
Workaround: Disable Javascript.

Written by Georgi Guninski