From: Jeff Gercken (JeffG@kizan.com)
Date: Fri Sep 03 2004 - 16:42:01 EDT
This thread has probably gone on for too long but I thought I'd add a
different approach.
Instead of looking at the workstations as black boxes from the network
you could look inside them for processes that have bound themselves to
sockets. You do have admin permissions right?
Microsoft (finally) has a good utility called Portqry (version 2 by Tim
Rains) that can do this. They also have a larger app called port
reporter that runs as a service and periodically reports on port usage.
portqry
http://support.microsoft.com/default.aspx?scid=kb;en-us;310099
GUI for portqry
http://www.microsoft.com/downloads/details.aspx?FamilyID=8355e537-1ea6-4
569-aabb-f248f4bd91d0&DisplayLang=en
port reporter
http://support.microsoft.com/?id=837243
log parser for port reporter
http://download.microsoft.com/download/2/8/8/28810043-0e21-4004-89a3-2f4
77a74186f/PRParser.exe
also try fport from foundstone
You could be especially sneaky and just routinely do remote kills of any
instances of IE, Firefox, etc you find on non-browsing hosts.
Pskill by Sysinternals
http://www.sysinternals.com/ntw2k/freeware/pskill.shtml
Or if you don't want to fuss with it you could just roll out group
policy and lock the things down. Or are you still using windows 98?
Lastly, you might just consider revoking the Internet restriction. If
you deny a thing, that's what people will want. By playing the game
you're actually encouraging people (at least ppl like me) to try and
defeat your control mechanisms. Open it up and you'll probably see
that, after a few weeks, it'll loose its luster.
-jeff
-----Original Message-----
From: Gary E. Miller [mailto:gem@rellim.com]
Sent: Thursday, September 02, 2004 8:04 PM
To: Jose Maria Lopez
Cc: pen-test@securityfocus.com
Subject: Re: Tool to find hidden web proxy server
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
Yo Jose!
On Thu, 2 Sep 2004, Jose Maria Lopez wrote:
> But if you allow in and out from specific ports you have at least a
> second level of security over what the original poster said it had.
> Only allowing out from some IPs it's possible, but I find it very
> difficult to make rules for the outer IPs, having in mind the original
> poster wants to have internet connection from the LAN for that
> machines.
If you leave just ONE port open, then an insider can use it to tunnel
out. That one port is often DNS/udp. You have to work very, very,
hard to filter out IP over DNS/udp. You could force the use of
an internal DNS server, but if it allows any recursive lookups out
of the firewall then game over.
This /. describes how to do it:
http://slashdot.org/articles/00/09/10/2230242.shtml
The insider does not even need an open port. Only TCP/IP (proto 6) and
TCP/UDP (proto 17) use "ports". The insider can just use a "portless"
protocol like TCP/ICMP (proto 1), TCP/ESP (proto 50), TCP/AH (proto 51),
etc.
There are several IPSEC stacks available as freeware that use TCP/ESP
and TCP/AH.
RGDS
GARY
-
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