Locating rogue APs

Tony Rall trall at almaden.ibm.com
Tue Feb 11 20:02:34 UTC 2003


On Tuesday, 2003-02-11 at 13:42 CST, "Matthew S. Hallacy" 
<poptix at techmonkeys.org> wrote:
> On Tue, Feb 11, 2003 at 11:27:28AM -0600, John Kristoff wrote:
> > In general, MAC OUI designations may indicate a particular AP.  IP
> > multicast group participation may also be used by some APs. Some
> > APs have a few unique ports open.  Lastly, APs may be found with
> > a radio on a particular default channel.  All of these potentially
> > identifying characteristics may be used to help audit the network
> > for rogue IPs.
> 
> Why are you posting this here? The information is somewhat 
incomplete/incorrect
> as well. Persons interested in finding rogue AP's would be much better
> off with a tool such as kismet that already identifies model/make of
> access points based on various datapoints (including the types you 
posted),
> as well as the ability to determine in where the AP is (pysically) with
> the use of a GPS unit.

It appears that kismet requires either someone to walk around the facility 
while running the program or that you have you have it installed on 
machines all over your site.  Neither of those options interest me as a 
long term solution to rogue AP monitoring.

It sounds like John is referring to using a network IDS system, maybe one 
per subnet, to try to infer from the wired (maybe) network traffic that an 
unwanted AP is connected to your wired network.  Given that you may want 
to run such an IDS anyway, this could give you a decent start on handling 
rogues.

Personally, I think the idea of checking radio traffic to be a more 
complete solution, but don't want to have to install a bunch of wireless 
machines all over the site to detect this.  I'm really waiting for the AP 
vendors to incorporate a rogue detection system in the APs itself.  This 
could solve the problem for those sites that have fully deployed APs.

Tony Rall



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