Slashdot Mirror
Domain: portknocking.org
Stories and comments across the archive that link to portknocking.org.
Stories · 2
-
Going Beyond Port Knocking; Single Packet Access
michaelrash writes "I have just released a new version of fwknop that implements a single-packet authorization scheme using libpcap (similar to what Simple Nomad has proposed for the upcoming BlackHat Briefings). Fwknop has made Slashdot once before as the first tool that combines port knocking and passive OS fingerprinting. However, this new single-packet method has many advantages over port knocking, including non-replayable messages, much more data can be sent (including complete commands), an attacker cannot break sequences simply by connecting to spurious ports on the target, and more. By using Netfilter to intercept packets within the kernel, anyone scanning for a service protected by this method cannot even talk directly to the IP stack without being authorized; that makes even 0-day exploits largely toothless." -
"Port Knocking" For Added Security
Jeff writes "The process of Port Knocking is a way to allow only people who know the "secret knock" access to a certain port on a system. For example, if I wanted to connect via SSH to a server, I could build a backdoor on the server that does not directly listen on port 22 (or any port for that matter) until it detects connection attempts to closed ports 1026,1027,1029,1034,1026,1044 and 1035 in that sequence within 5 seconds, then listens on port 22 for a connection within 10 seconds. The web site explains it in some detail, and there is even an experimental perl implementation of it that is available for download. I can't think of any easy ways you could get around a system using this security method - let alone even know that a system is implementing it. Another article on port knocking is here."