802.1x is a good starting point.  I'd go on to say it's far from absolute.  
Rogue detection is critical (multiple ways to do it and many good tools,,,due 
diligence is in order.)  

If you're responsible for your wifi security you should know exactly where 
every AP is located; you should have some *tool* that maps them; you should be 
able to identify rouge AP's in short order.  

If you have 802.1x, you know where all your AP's are, you have a rock solid map 
of your entire network, etc, etc, etc, you're still at risk.  You must be as 
aggressive as your corporate food-chain will allow (once you find what the 
limitation is I recommend pushing just a bit further.)


 

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Bourque Daniel
Sent: Thursday, March 22, 2007 7:46 PM
To: Eric Hacker; [email protected]
Subject: RE: Wired detection of rogue access points

No solution is absolute.

Activate 802.1x Port base auth on your network and you increase the level of 
expertise necessary to connect a rogue AP.
Install Wifi sensors on every floor of every building and use something like 
AirDefense to centrally manage them. 
Scan the network from the wire side.
Install agent on all your laptops to disable the WiFi port as soon as the 
Ethernet port is active.
Put filters on your vlans so that PC cannot talk across vlan to other PC but 
only at the server's vlan.  A good structure IP Address plan is very helpfull 
for that Etc...




-----Message d'origine-----
De : [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] De la part de Eric Hacker 
Envoyé : 21 mars 2007 14:11 À : [email protected] Objet : Re: Wired 
detection of rogue access points

Haven't we gone through this before?

For each of you that thinks they have a way to detect a wireless access point 
using only the LAN, please demonstrate how you would detect this.

A wireless router is hooked up to the network jack of a printer. The wireless 
router is configured to use the printer's MAC address. The wireless router is 
set up with the printer's new IP address as it's DMZ  host[1]. From the 
outside, all port scans and probes are going to the printer.

There might be some IP stack differences, but you'd have to have a very 
comprehensive database to figure that out, and the time to scan at that level 
could prevent that level of probing on large networks.

>From Mr. Waters, I expect no less than the results of an actual scan on a live 
>network with this set up running on it. :)

Now that was easy. No real expertise required on the person who set up the 
rogue access point, just a little cleverness. So lets say I want to put the 
rogue access point on your network.

Same router, new firmware. My new OS is reconfigured a bit.

The WAN port bridges to LAN1. WAN plugged in to wall, LAN1 plugged in to 
printer. All other ports and the wireless are configured for the private LAN on 
the router.

My OS sniffs packets and determines the IP address in use by the printer. Now 
it statefully NAT's packets from it's private network to the printer's IP 
address. It filters return packets on the bridge so that the printer doesn't 
see any of the traffic.

Now how do you find it over ethernet with scanning or probing? It doesn't 
respond to anything. It doesn't interfere with the printer's IP stack 
fingerprints when the printer is probed. Only watching the unusual traffic 
coming from the printer or scanning for the RF would pick this up.

Oh yeah, heaven forbid that I go all out and not use normal wireless 
frequencies. Maybe pop in an EVDO card instead of an 802.11 one. Who would want 
their own Internet accessible back door into your intranet anyway?

OK, so my OS isn't completely off the shelf, and I haven't had the time to sit 
down and make it work yet. The open source pieces are all there, however, just 
waiting for the right person to come along and duct tape them all together.

Bottom line: Ethernet cannot be completely secured. Either encrypt everything, 
watch everything, or physically control access to everything.

Regards,
Eric Hacker, CISSP

[1] I hate using the term DMZ for this use, but that's what is used on all the 
router configurations.

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