RE: Vulnerability testing in analog modem

["Craig Wright" <Craig.Wright () bdo com au>]

Some modems (most actually these days) have a Fax capability, However, most Fax machines do not have a modem function. 
A modem is not a fax and visa versa.

 There is no currently known means to compromise a Fax machine and get onto a network. There is no theoretical scenario 
where this is possible that has been proposed.

You can not bridge a network over the fax protocols. You could create a device that would do this, but it would be 
needed on each end and would be in effect a modem taking the analogue fax signal and changing it to a digital 
connection and back.

So what this comes to is are you testing modems - which can be used to create a link or faxes? A modem bank used as a 
fax service is NOT a fax machine.

When connected to a FAX machine over the fax protocol, there is no bridge. It is an analogue signal and is never 
converted into any networked protocol. Faxes do not work like modems.

 So to conclude, there is no test as you never make a connection to a fax machine in the manner that you suspect.

What you are suggesting is that you can get a modem connection (if the fax machine is not a fax machine, but a modem 
simulating a fax). Even this is incredibly difficult if the device is set as a fax alone.

Regards,

Craig Wright

GSE-Compliance




Craig Wright
Manager of Information Systems

Direct : +61 2 9286 5497
Craig.Wright () bdo com au
+61 417 683 914

BDO Kendalls (NSW)
Level 19, 2 Market Street Sydney NSW 2000
GPO BOX 2551 Sydney NSW 2001
Fax +61 2 9993 9497
www.bdo.com.au

Liability limited by a scheme approved under Professional Standards Legislation in respect of matters arising within 
those States and Territories of Australia where such legislation exists.

The information in this email and any attachments is confidential.  If you are not the named addressee you must not 
read, print, copy, distribute, or use in any way this transmission or any information it contains.  If you have 
received this message in error, please notify the sender by return email, destroy all copies and delete it from your 
system. 

Any views expressed in this message are those of the individual sender and not necessarily endorsed by BDO Kendalls.  
You may not rely on this message as advice unless subsequently confirmed by fax or letter signed by a Partner or 
Director of BDO Kendalls.  It is your responsibility to scan this communication and any files attached for computer 
viruses and other defects.  BDO Kendalls does not accept liability for any loss or damage however caused which may 
result from this communication or any files attached.  A full version of the BDO Kendalls disclaimer, and our Privacy 
statement, can be found on the BDO Kendalls website at http://www.bdo.com.au or by emailing administrator () bdo com au.

BDO Kendalls is a national association of separate partnerships and entities.

________________________________


From: listbounce () securityfocus com on behalf of firstkhan2000 () yahoo com
Sent: Fri 26/10/2007 11:49 PM
To: security-basics () securityfocus com
Subject: Vulnerability testing in analog modem



All of us know that a fax machine should not be on a corporate network because it has dial in/out capability on one 
side and connected to the NW on the other - thus, creating a bridge to the NW thru the insecure modem connection. As a 
security person, I would like to test it by dialing into the fax machine, and thru the established bridge, enter into 
the network, and see what's the exposure.

What would be the best way to conduct this test? I would be grateful if someone could point me to a step by step 
testing situation/document.

Best Regards,

First Khan
347-452-1845