RE: NMAP Identity obscuring

["Ofir Arkin" <ofir () itcon-ltd com>]

Cameron,

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.
http://www.itcon-ltd.com

Founder
http://www.sys-security.com

"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?

cameron.


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
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> 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
slowness.

- Oliver

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