full-disclosure - Re: Re: ICMP Destination Unreachable Port Unreachable

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Wed, 16 Aug 2006 08:37:00 -0400
From: Valdis.Kletnieks@...edu
To: Barrie Dempster <barrie@...oot-robot.net>
Cc: full-disclosure@...ts.grok.org.uk
Subject: Re: Re: ICMP Destination Unreachable Port
	Unreachable

On Wed, 16 Aug 2006 12:33:13 BST, Barrie Dempster said:
> Although the port 0 in this case is a red herring and irrelevant. Port 0
> itself when used with TCP/UDP (not ICMP!) can actually be used on the
> Internet. A while back I modified netcat and my linux kernel so that it would
> allow usage of port 0 and was able to connect to a remote machine via TCP
> with that port and communicate fine.

Of course, the poor security geek who see a TCP SYN from port 0 to port 0,
and then a SYN+ACK reply back, will be going WTF??!? for the rest of the day. :)

(Another good one to induce head-scratching is anything that does
RFC1644-style T/TCP.  Anytime you see a packet go by in one direction with
SYN/FIN *and* data, and the reply has SYN/ACK/FIN and data.. ;)
data on it... ;)

Content of type "application/pgp-signature" skipped

_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
Hosted and sponsored by Secunia - http://secunia.com/