Full Disclosure mailing list archives

RE: how to bypass rogue machine detection techn iques


From: "Fetch, Brandon" <BFetch () texpac com>
Date: Mon, 11 Jul 2005 17:42:50 -0500

I was going to suggest the same thing.

There are methods of configuring (Cisco) switches to have their default VLAN
be an innocuous network that's boxed in and/or be prompted with a default
login or proxy page to allow packets to pass.

More specifically - the port is 'VLAN authenticated' and made a member of
the correct VLAN based upon the provided & verified credentials/role.

Cisco NAC & their 'Self Defending Network' propag..er marketing material.
;-)
(may wrap)
http://www.cisco.com/en/US/netsol/ns340/ns394/ns171/ns413/networking_solutio
ns_package.html

Unfortunately I'm not too familiar with what else exists for non-Cisco
networks/switches but it comes down to stopping any potential client/node
from illicitly transmitting across your wire/frequency to cause problems
from the beginning.

But we were talking about detecting rouge machines...
Put a bunch of mirrors around the office to show how silly a machine looks
in rouge?
:-)

HTH,
Brandon


-----Original Message-----
From: Devdas Bhagat [mailto:devdas () dvb homelinux org]
Sent: Monday, July 11, 2005 4:16 PM
To: full-disclosure () lists grok org uk
Subject: Re: [Full-disclosure] how to bypass rogue machine detection
techniques


On 12/07/05 00:55 +0530, Gaurav Kumar wrote:
thanks a lot everybody.

Spelling in subject corrected.


now i am just wondering if the detection technique can be integrated
at the switch level. for example, one software can connect to switch
via ssh, and collect the ipaddress information of the machine trying
to plug in to the network, as soon as we detect this machine, we can
connect to it to test whether its a part of trusted domain/network or
not.


You would need to trigger the scan when the host is plugged into the
switch. The device also needs to respond to an ARP request of some sort.

What happens if I plug in a dumb hub into the switch, and then a laptop
with no IP address on the NIC and ARP disabled into the hub?

Keep in mind that switches are designed to fail open, so I just need to
flood the switch with a very large number of MAC addresses to convert it
into a nice broadcast device.

i think even if a box is in stealth mode, we can still detect it if we
use our detection mechanism at switch level itself.

Possible. However, in most cases, it is easier to implement proper
physical security and not let random people connect from nodes all over
the place. Using 802.1x is useful as well.

Devdas Bhagat
<snipped>
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