Re: PCI DSS 11.1 - ".. deploying a wireless IDS/IPS..". Kismet+Snort?

[Joel Snyder <Joel.Snyder () Opus1 COM>]

> The reason is that you cannot completely deploy 802.1x today. If EVERY port
> required 802.1x authentication then you could argue that no unauthorized
> devices could be connected. The problem is that not all network devices
> support 802.1x today. 

Yes, this is true, but there is a common strategy in NAC where 802.1X 
fails over to MAC authentication.  Thus, you would say that a printer 
with a known MAC address can connect to a particular port, but if 
someone attached a different device to the port (with a different MAC 
address), then the port would not open up.  In Cisco-speak, they call 
this MAC Address Fallback, but all modern switches allow for it.

> Examples include printers, IP cameras, networked
> scanners, and (sadly) access points. So, because you need to provide for
> these exceptions you cannot guarantee that no excepted device has been
> unplugged and an unauthorized device plugged in in it's place.

Now, of course, anyone with a strong knowledge of networking is aware 
that MAC addresses can be cloned (in fact, access points often make this 
easy to help work-around MAC limitations by broadband ISPs), and thus 
the use of the word "guarantee" is a very difficult one.  But you might 
also claim (in fact, I'd be happy to claim this) that someone who is 
intentionally subverting network security would also be easily capable 
of avoiding a wireless IDS/IPS scanner.

Thus a wireless IDS/IPS scanner might help to tune the window of 
vulnerability down, but at what potential cost?

(I am not arguing against wireless IDS, by the way; I am just asking 
these questions to get some general ideas out on the table and see how 
domain experts in the PCI area are reacting--whether NAC provides a 
"guarantee" if implemented correctly, for example)

As long as I'm throwing hard questions out there: how many people with 
wireless IDS/IPS are, perhaps illegally, using a different regulatory 
regime in order to catch the clever attacker who is using channel 120 in 
Fargo (an EMEA-only channel) or channel 165 (a US-only channel) in Florence?

jms


--
Joel M Snyder, 1404 East Lind Road, Tucson, AZ, 85719
Senior Partner, Opus One       Phone: +1 520 324 0494
jms () Opus1 COM                http://www.opus1.com/jms