IDS mailing list archives

RE: Wired detection of rogue access points


From: "Adam Graham" <agraham () datastreamcowboys net>
Date: Wed, 28 Mar 2007 11:55:51 -0500

Why is everyone concentrating on MAC filtering..... MAC filters are just a
front line first wave deterrent. Yeah anyone can go download sirMacsalot and
spoof their MAC easily. The key is that wireless equipment should not be
trustedI placed mine outside the firewall, so users must use the VPN to get
in, because I trust Firewall/VPN equipment 1000 times more than any wireless
equipment 

-----Original Message-----
From: Adam Powers [mailto:apowers () lancope com] 
Sent: Wednesday, March 28, 2007 9:41 AM
To: tim_holman () hotmail com; Adam Graham; listbounce () securityfocus com;
Focus-Ids@Securityfocus. Com
Subject: Re: Wired detection of rogue access points

"Filtering by MAC gives you no additional security whatsoever, period"

Meh, this is simply not true. My home AP might is plenty secure from my SOHO
technology noob neighbors with MAC filtering - few, if any, of them even
know what an "AP" is much less "MAC spoofing".

Having said that filtering technologies such as MAC filtering are far too
difficult to manage given the relatively small security return provided and
as such should be avoided given the fact that other superior authentication
and access control mechanisms exist.



On 3/26/07 7:24 PM, "tim_holman () hotmail com" <tim_holman () hotmail com> wrote:

Filtering by MAC gives you no additional security whatsoever, period.  MAC
addresses can be easily spoofed and although your solution may assist in
spotting misconfigurations a determined intruder will get straight
through....

Sent from my BlackBerryR wireless device

-----Original Message-----
From: "Adam Graham" <agraham () datastreamcowboys net>
Date: Mon, 26 Mar 2007 15:52:21
To:<focus-ids () securityfocus com>
Subject: RE: Wired detection of rogue access points

First off is it even possible to buy a laptop that does not have wifi
built
in?

I have set up an automated scan looking for MACs. If the MAC does not
appear
on my list I drop its packets in the IPTabes FW. It's rather simple to do.
The main thing I do that seems to work the best is the APs are un-trusted
and therefore stuck out in the DMZ. Before one can get to network
resources
they need to open the VPN client after connecting to the AP.

A simple way to handle MACs with IPTables (NOTE: simple rule if you need
more instruction I can send it to you or just the complete iptable
script):

Let's create 2 text files:
/tmp/whiteist
/tmp/blackist

Insert into whiteist  00:06:25:2E:56:A0
Insert into blackist  00:06:25:2E:56:E1


Add following to your IPTabes script
TABLES = "filter nat mangle"
iptables = /sbin/iptables
touch /tmp/whiteist
touch /tmp/blackist
WHITELIST = `cat /tmp/whiteist | awk '{print $1}'
BLACKLIST = `cat /tmp/blackist | awk '{print $1}'

# Forward good MACs
$iptables -t filter -I FORWARD 1 -m mark --mark 0x42 -j ACCEPT

# mark all packets from the good macs
for MAC in $WHITELIST ; do
$iptables -t mangle -I PREROUTING -m mac --mac-source $MAC -j MARK
--set-mark 0x42
done

# drop all packets from the good macs
for MAC in $BLACKLIST ; do
$iptables -t mangle -I PREROUTING -m mac --mac-source $MAC -j DROP
done





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-- 

Adam  Powers
Chief Technology Officer
Lancope, Inc.
c. 678.725.1028
e. adam () lancope com


__________ NOD32 2148 (20070327) Information __________

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