Date:	Mon, 24 May 1999 14:24:13 +0300
From:	Georgi Guninski <joro@NAT.BG>
Subject:      Netscape Communicator JavaScript in <TITLE> security vulnerability
To:	BUGTRAQ@NETSPACE.ORG

There is a security bug in Netscape Communicator 4.6 Win95, 4.07 Linux
(guess all 4.x versions are affected) in the way they treat JavaScript
code
in the title of the document.

One may embed JavaScript code in the <TITLE> tag. If the info about the
document
is shown, then the JavaScript code is executed. The info about the
document
may be infoked by a script using 'location="wysiwyg://1/about:document"
'.

The problem is that the JavaScript code is executed in the security
context
of the "about:" protocol. This allows accessing documents in the
"about:"
protocol such as: "about:cache", "about:config", "about:global", etc.

Vulnerabilities:
 * Reading user's cache and accessing information such as passwords,
credit card
  numbers.
 * Reading info about the Netscape's configuration ("about:config").
This includes
  finding user's email address, mail servers, the encoded mail password
  (it must me saved and may be decoded). This allows reading user's
email.

The more dangerous part is that this vulnerability MAY BE EXPLOITED
USING HTML MAIL MESSAGE.


Workaround: Disable JavaScript

Demonstration is available at: http://www.nat.bg/~joro/titlecache.html

Georgi Guninski
 http://www.nat.bg/~joro
 http://www.whitehats.com/guninski