Setting Up a Router:

[James Michael Fultz]

* Andrew Farris <flyindragon1 at aol.com> [2009-10-02 22:16 -0500]:
> BSSID & MAC-filtering in general aren't useless, are they? or perhaps
> just on your Verizon thingy? I thought at least mac-filtering was
> reasonably secure... I basically just quit caring enough about it to
> research it after I trashed my last wireless router...

Unless you want to run an open AP, best to use WPA/WPA2 with AES or --
if you must -- a WEP with a frequently rotated key.

<http://blogs.zdnet.com/Ou/index.php?p=43>

"MAC filtering: This is like handing a security guard a pad of paper
with a list of names. Then when someone comes up to the door and wants
entry, the security guard looks at the person's name tag and compares it
to his list of names and determines whether to open the door or not. Do
you see a problem here? All someone needs to do is watch an authorized
person go in and forge a name tag with that person's name. The
comparison to a wireless LAN here is that the name tag is the MAC
address. The MAC address is just a 12 digit long HEX number that can be
viewed in clear text with a sniffer. A sniffer to a hacker is like a
hammer to a carpenter except the sniffer is free. Once the MAC address
is seen in the clear, it takes about 10 seconds to cut-paste a
legitimate MAC address in to the wireless Ethernet adapter settings and
the whole scheme is defeated. MAC filtering is absolutely worthless
since it is one of the easiest schemes to attack. The shocking thing is
that so many large organizations still waste the time to implement these
things. The bottom line is, MAC filtering takes the most effort to
manage with zero ROI (return on investment) in terms of security gain."

<http://www.oreillynet.com/pub/a/wireless/excerpt/wirlsshacks_chap1/>

"I know of two ways to find valid MAC addresses for a given network. You
could associate with the AP and run an IP layer network sniffer such as
Ethereal or tcpdump).This is, of course, the hard way, particularly if
you already have Kismet handy.

"The easy way is to select the network you are interested in (hit ss to
sort by SSID, and arrow down to it if necessary) and then view the
associated clients (hit c). Presto, you have a list of MAC addresses for
clients that are using the network, and presumably are on the permitted
MAC table. Wireless clients send their MAC address in the clear,
regardless of whether the AP requires WEP or not."