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RE: Port-Knocking vulnerabilities?
From: "Craig Wright" <Craig.Wright () bdo com au>
Date: Tue, 1 Jan 2008 08:13:27 +1100

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.

Dr Craig Wright (GSE-Compliance)

Craig Wright
Manager of Information Systems

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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.

Ansgar Wiechers
"The Mac OS X kernel should never panic because, when it does, it
seriously inconveniences the user."

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