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RE: Port-Knocking vulnerabilities?
From: "Jay" <jay.tomas () infosecguru com>
Date: Mon, 31 Dec 2007 12:31:01 -0500

You obviously haven't looked into the technology and don't understand basic concepts of authentication.

Lets review - Authentication - proving you are who you say your are.

1)Something you know - password, pin number, sequence of agreed upon ports to knock before a separate service starts to 
listen to furter authenicate or authorize access to server.

2)Something you are - fingerprint, retina scan, DNA.

3)Something you have - keyfob, certificate.

Like any technique, it is merely 1 layer of the defense. It can be implemented in a weak way that provides little to no 
defense or more complex way effectively adding to the layers of defense.

I know you will respond to this please keep it to under 3 pages. You aren't going to change my mind or understanding of 
basic security concepts. I posted this for the benefit of those on the list that are truly trying to learn security 
basics.

Jay

----- Original Message -----
From: Craig Wright [mailto:Craig.Wright () bdo com au]
To: tomc () targetbilling com,kappaalphapieta () hotmail com
Cc: security-basics () securityfocus com
Sent: Sat, 29 Dec 2007 06:48:50 +1100
Subject: RE: Port-Knocking vulnerabilities?

Port Knocking is obfuscation and not a security technique. It was and is designed not as a security function, but as a 
channel to hide communications on compromised hosts.

It is a hacker toy and not a security tool. It is as effective as turning on the ?IP Security? flags in a packet (just 
use hping and away you go).

Regards,
Dr Craig Wright (GSE-Compliance)



Craig Wright
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________________________________________

From: listbounce () securityfocus com [listbounce () securityfocus com] On Behalf Of Tom Corelis [tomc () targetbilling 
com]
Sent: Saturday, 29 December 2007 5:20 AM
To: Kappa Alpha Pi Eta
Cc: security-basics () securityfocus com
Subject: RE: Port-Knocking vulnerabilities?

I suppose you could do two successive port scans and hope the second
completes before the port-knockers' threshold.....


--
Tom Corelis
TBC IT

-----Original Message-----
From: listbounce () securityfocus com [mailto:listbounce () securityfocus com]
On Behalf Of Kappa Alpha Pi Eta
Sent: Friday, December 28, 2007 7:12 AM
To: security-basics () securityfocus com
Subject: Port-Knocking vulnerabilities?


Hi listers.

so I read this thread about port-knocking (altough called "reflexsive
firewalls"). I'd never heard of that and found that to be an very
interesting mechanism. Now I just keep wondering, what an attacker could
possibly do to intrude system secured in such a way. So there are no
open ports at all, also, there's no way the attacker could access the
computer physically or via social engineering. The attacker knows that a
knock-server is running and that there's some daemon waiting to become
accessible (what ever that may be).
What could a attacker do to somehow get access to that machine? And how
can I secure that machine from that kind of attacks.

Thanks in advance,
Kajin
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