Home page logo

Nmap Announce mailing list archives

RE: NMAP Identity obscuring
From: "Ofir Arkin" <ofir () itcon-ltd com>
Date: Wed, 22 Nov 2000 14:47:55 +0200


I have read the Article in the sysAdmin magazine, unfortunately it is not
enough to fool me :)

The article, for those who do not subscribed to SysAdmin, deals with
changing parameters with
Solaris so NMAP will not detect it. The article suggests changing the PMTU
policy, and harden the sequence
numbers sequencing.

But, there are a lot of other wild ideas we can use that will reveal the
Solaris box.
Changing the most common identification parameters will not hide the other
Sure, it will make the job harder, but not impossible.

Ofir Arkin  [ofir () itcon-ltd com]
Senior Security Analyst
Chief of Grey Hats
ITcon, Israel.


"Opinions expressed do not necessarily
represent the views of my employer."

-----Original Message-----
From: Cameron Palmer [mailto:cameron_palmer () hotmail com]
Sent: Sunday, November 05, 2000 2:50 AM
To: of () securityfocus com; ofir () itcon-ltd com; lance () spitzner net
Cc: nmap-hackers () insecure org
Subject: NMAP Identity obscuring

I know we have seen the argument before, but the recent SysAdmin magazine
has an article on Solaris security.  They recommend changing some NDD
parameters to obscure the identity of Solaris from nmap.  They have some
interesting points, which is essentially they aren't looking for that as the
sole form of protection of the machine but merely make Solaris conform to
the RFCs instead of having its own quirks that give away too much
information.  I would normally be dissuaded from security by obscurity
arguments, but by taking out the things that make the OS unique and conform
to RFCs you do raise the ante as it were.  Additionally I've seeen some
other good OS tuning parameters with NDD that help performance that are a
good idea, like fixing your Quad card to having multiple MAC addresses
instead of the single hostid.  Apparently you can gain a 40% speed boost on
a Checkpoint firewall. This came from the Checkpoint web site.  They have a
number of recommendations for security related changes.

Any thoughts?


From: Oliver Friedrichs <of () securityfocus com>
To: Ofir Arkin <ofir () itcon-ltd com>, Lance Spitzner <lance () spitzner net>
CC: nmap-hackers () insecure org
Subject: RE: firewalk meets nmap - TTL (tested)
Date: Sat, 04 Nov 2000 15:36:23 -0800
MIME-Version: 1.0
Received: from mta1.snfc21.pbi.net (mta1-pr) by sims1.snfc21.pbi.net (Sun
Internet Mail Server sims.3.5.2000. with ESMTP id
<0G3I00609XSQ25 () sims1 snfc21 pbi net> for palmer74 () sims-ms-daemon; Sat, 4
Nov 2000 15:41:14 -0800 (PST)
Received: from amy.insecure.org ([]) by mta1.snfc21.pbi.net
(Sun Internet Mail Server sims.3.5.2000. with SMTP id
<0G3I000N7XQ0PL () mta1 snfc21 pbi net> for palmer74 () sims1 snfc21 pbi net; Sat,
04 Nov 2000 15:39:37 -0800 (PST)
Received: (qmail 20825 invoked by uid 508); Sat, 04 Nov 2000 23:46:19 +0000
Received: (qmail 20725 invoked from network); Sat, 04 Nov 2000 23:41:28
Return-path: <nmap-hackers-return-887-palmer74=pacbell.net () insecure org>
Message-id: <10786F3AE30CD4118FAC00A0CC58F9F1015929 () MAIL>
X-Mailer: Internet Mail Service (5.5.2650.21)
Precedence: bulk
Delivered-to: mailing list nmap-hackers () insecure org
Delivered-to: moderator for nmap-hackers () insecure org
Mailing-List: contact nmap-hackers-help () insecure org; run by ezmlm

Lance, we should automate this somehow. This is a cool thing.
But again correct configuration will prevent this from happening.

This is a really neat idea.  It should be easy to automate, if you
add in some traceroute functionality to nmap to determine the hop
where packets are being dropped (this would be the firewall), then
you only need to specify an address on the internal network.  I think
nmap could use UDP/TCP ACK/ICMP traceroute functionality anyways.
And while your at it, make it parallel, send out 32 packets with
incrementing ttl's at the very start.. none of this 1 hop at a time

- Oliver

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).

Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.

Share information about yourself, create your own public profile at

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).

  By Date           By Thread  

Current thread:
[ Nmap | Sec Tools | Mailing Lists | Site News | About/Contact | Advertising | Privacy ]