Nmap Announce mailing list archives
RE: Updated scanning techniques
From: "Robert Purdy" <liteyear () ihug co nz>
Date: Sun, 10 Sep 2000 11:10:59 +1200
I think Lance is right here. Since version 4.1? / and definitely 4.1 SP2 Checkpoint has changed how it deals with established conections. Prior to 4.1 SP2 it used to try and recover the connections that weren't in the connections table. From 4.1 SP2 and on, (I assume), it instead drops the connection and logs it as a unknown established TCP packet on Rule 0. Eariler versions tried to recover the session but if it failed would log as either an error on unknown reason 12 or drop rule 0. We had this problem migrating from 4.0 to 4.1SP2. Cheers Rob Purdy Whereas FireWall-1 versions prior to 4.1 SP2 used to try and recover TCP connections for which it did not have a connections table entry, it now simply drops these packets on the floor on rule 0 with this error message.
-----Original Message----- From: Dug Song [mailto:dugsong () monkey org] Sent: Sunday, 10 September 2000 9:06 a.m. To: Lance Spitzner Cc: nmap-hackers () insecure org Subject: Re: Updated scanning techniques On Sat, 9 Sep 2000, Lance Spitzner wrote:1. -sA -sA is not the option of choice any more for newer firewalls, such as CheckPoint FW-1 ver 4.1 SP2. As most of you know, -sA is designed to validate firewall rulebases using ACK packets. However, newer firewalls only allow SYN packets to build a session in the state table, so you can no longer initiate connecitons with an ACK packet.are you sure this is what's happening? from what i've heard, upon receipt of an ACK not associated with an existing connection, Firewall-1 passes the ACK through as a window probe (no payload) and intercepts any response from the destination itself to determine if the connection actually exists (as it might in the case of a firewall reboot). the end result is the same, nmap-wise, but a bit different wrt the stateful inspection mechanism at work. -d. --- http://www.monkey.org/~dugsong/ -------------------------------------------------- For help using this (nmap-hackers) mailing list, send a blank email to nmap-hackers-help () insecure org . List run by ezmlm-idx (www.ezmlm.org).
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Current thread:
- Updated scanning techniques Lance Spitzner (Sep 12)
- Re: Updated scanning techniques Lennert Buytenhek (Sep 12)
- Re: Updated scanning techniques Nelson Brito (Sep 12)
- Re: Updated scanning techniques Dug Song (Sep 12)
- RE: Updated scanning techniques Robert Purdy (Sep 12)
- Re: Updated scanning techniques Lance Spitzner (Sep 12)
- Re: Updated scanning techniques Darren Reed (Sep 12)
- Re: Updated scanning techniques Lennert Buytenhek (Sep 12)