RE: MORE: Tools for Detecting Wireless APs - from the wire side.

From: Jon (vandivee@midsouth.rr.com)
Date: Wed Jun 12 2002 - 00:18:16 EDT


Come come....
The cheap appliances can well indeed change their MAC...

I can clone my 3Com NIC, publish it to the wire and run my AP virtually
undetected.
(I forgot this or else I would have included it when I proposed the MAC
OUI polling from the switch, course most "users" won't know this)

The only way I can see to secure your LAN from having rouge APs attached
is something I have only heard of and never seen.

EAP based authentication for port security....

And with that.... I can honestly say I have NO IDEA how to do it right
now.....

If anyone has a whitepaper for implementation EAP for port security,
please post it or send it to me...

Thanks,
Jon

-----Original Message-----
From: Weaver, Woody [mailto:woody.weaver@callisma.com]
Sent: Monday, June 10, 2002 9:12 PM
To: R. DuFresne; Isherwood Jeff C Contr AFRL/IFOSS
Cc: 'Pen-Test'
Subject: RE: MORE: Tools for Detecting Wireless APs - from the wire
side.

On Monday, June 10, 2002 3:45 PM, R. DuFresne wrote:
[..]
>MAC addresses can not only be spoofed and changed, but, looking at just
>3Com, one gets an idea of the large number of MACs one has to keep
track
>of.

Ron, I'm not sure of your point here. If we are assuming a non-compliant
employee (user or administrator) then they have probably deployed a
commercial access point. These are typically on appliance devices, and
can't
change their MAC. (Remember, the point is to find the AP, not find who
is
connecting on the wireless side.)

Keeping track of MAC OUIs is not difficult, since
http://standards.ieee.org/regauth/oui/oui.txt takes care of that for
you.

Essentially, the task comes down to looking at each MAC, and asking
"what is
this device?" This is a useful exercise, irrespective of the problem of
wireless access.

Once the APs have been identified, the next step is to determine the
consequences of the AP -- which is where the rest of the content in your
note applies.

In an environment with a black hat, things are much more difficult. The
AP
is likely to be part of a general purpose operating system, where nmap
et
alia will be useless. A really stealthy box won't respond to a port
scan,
but can pass traffic. The advantage of the ARP cache (or better CAM
tables)
approach is that the box *has* to populate a cache at layer 2 to
communicate. It might be spoofed, or fraudulent, but *something* has to
show
up. This is the same problem as a stray modem or T1 -- how do you find a
modem if its on a ringback?

--woody

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