From:	derek@***************.com (Derek Hyde)
Subject:	Hacking a Smartlink in SR4
Date:	Wed, 05 Oct 2005 01:36:26 -0500

>
>> You _can_ control access to a network by restricting which MAC
>> addresses can connect to it, but it's not much of a security measure.

It's what? Have you done much networking? MAC Filtering to only allow
pre-programmed MAC addresses in the router, is one of the most difficult to
get around methods of network security there is. It's far better than
software firewalls or anything else of the sort, because if your MAC address
doesn't match one in the list of acceptable MAC addresses, you simply don't
have access to the network at all.

Here's an example:
Wireless Router is set to broadcast SSID, has a WEP Password, and MAC
Address Filtering to only allow 2 computers whose addresses are already
stored.

You try to connect to it, your wireless card finds the SSID, you tell it to
connect, it asks for the WEP Password, you give it the correct password, it
checks your MAC address, validates, DHCP server on the router assigns you an
IP address, you've got internet or intranet connectivity.

If you fail any of those points before the MAC filter, you'll just get
denied, if you fail the MAC filter, you won't be given an IP address, and
the router simply won't process information to or from your system *at all*

Not even to try to get to the router config so you can fix that you're not
in there.

>
> As evidenced by, for example, my router's option of replacing the MAC
> address it says it has by the one of a connected device, or by a value I
> can enter myself.

Yes, you can do that to make the router appear to be a specific PC, but only
once you're ON the router and within it's network, if a router is setup to
only allow specific MAC addresses to access it, and not to broadcast it's
SSID, you likely will never get into it, unless of course you're just that
hot shit of a hacker, Gurth, I know you got an apple, I could suggest to you
in private where to get ahold of a pair of tools designed to do exactly
that, and then you take a computer other than your apple, setup your router
not to broadcast it's ID, and then setup mac filtering to only allow the
other computer, then start up the two apps on the apple and see how long it
takes you to get into your own network, (testing the theory in this manner
isn't illegal, as, there's nothing illegal about trying to hack your own
personal network). Routers are setup to be able to do that specifically
because there are ISP's that work off of the PC's MAC address for
authentication, and the router won't allow that MAC address to be seen as
it's inside the network. It's the only way that you can use any form of
network setup on such ISP's.


While I'm not saying that MAC filtering is uncrackable or whatnot, I am
saying that it's by far more secure than any other method of keeping people
out of a network when they're not authorized to access it.