RE: Port-Knocking vulnerabilities?

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

Jay,
You state I have not looked at this. I guess you have not looked at the threads from a year ago, and from before that 
and etc. This topic raises its ugly head from time to time when someone gets the idea that it is the great new thing.

If there alread is a password or similar, portknocking adds no value. The economic cost to the user is less then the 
gain. That is a loss. All improveemtns are bound on a gain/loss function. Limited resources equal limited places to put 
our effort and money.

You posted this not for the benifit of those that are truly trying to learn security basics, but yourself. As I stated, 
change the TCP flag options in all packets and you have gained as much (maybe more) then portknocking. It is a script 
kiddy toy designed to hide listening trojans. It is not a security tool and you are not helpiong those who do not know 
a lot about security by adding FUD to their knowledge.

Regards,
Dr 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 [listbounce () securityfocus com] On Behalf Of Jay [jay.tomas () infosecguru com]
Sent: Tuesday, 1 January 2008 4:49 AM
To: bugtraq () planetcobalt net; security-basics () securityfocus com
Subject: Re: Port-Knocking vulnerabilities?

Is portknocking a weaker security mechanism. Does that discount it completely.

Telnet and ftp our clear text. Just because something can be defeated doesn't mean it loses 'all' its classification
A door is meant to provide some defense to the outside of your house. I can certainly bash it in with a sledge hammer. 
It still serves its purpose as a layer of the defense.

Again we are talking about security basics here. You can say it isn't viable or is inherently weak. But the way it is 
implemented its used for authentication. Plain and simple.

----- Original Message -----
From: Ansgar -59cobalt- Wiechers [mailto:bugtraq () planetcobalt net]
To: security-basics () securityfocus com
Sent: Sat, 29 Dec 2007 14:28:53 +0100
Subject: Re: Port-Knocking vulnerabilities?

On 2007-12-28 Jay wrote:
> Portknocking is a security mechanism as it is a type of
> authentication. "Something you know" in this case the sequence of
> ports to knock before a unstarted service or daemon begins listening
> for connections.

Since everything is transmitted in the clear port-knocking is as much of
a security mechanism as cleartext passwords. Technically: maybe
(depending on your definition). Realistically: no.

Regards
Ansgar Wiechers
--
"The Mac OS X kernel should never panic because, when it does, it
seriously inconveniences the user."
--http://developer.apple.com/technotes/tn2004/tn2118.html