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In article <jenn_b.5@aci_1.aci.ns.ca>, jenn_b@aci_1.aci.ns.ca (JENNIFER BAKER) writes:
>What are some of the security measures to consider when dealing with 
>WIRELESS LANS.


1) Wireless LANS, at frequencies below 10GHz, are easy to monitor relatively
cheaply. (At the 10Ghz range, one has to intercept the path of the microwave
signal).
Commercial receivers are available that will happily monitor any frewuency
up to about 950 Mhz - If a TNC (with modem chip set for the correct baud rate)
is then connected in to a PC, packets received can be decoded and analysed
very easily.
An answer to this could be to use some form of publickey encryption. However
the basic problem with a wireless LAN is that it is essentially a 
broadcast medium, with the additional probelm that no physical connection to
the transmission link is needed.
An answer to this problem could be using Infra-Red laser transmission, if
your establishment has the necessary line-of-sight links. Since this
is of a much higher frequency, it will be harder to intercept (minimal
dispersion) and also your data rate will be much better (enough to run 
boot/swap over NFS :) ).
I would be interested to read followups on this topic - and also what the 
eventual solution to this project was.

Jon Care,
jon_care@hicom.lut.ac.uk

jon_care@hicom.lut.ac.uk writes:

>In article <jenn_b.5@aci_1.aci.ns.ca>, jenn_b@aci_1.aci.ns.ca (JENNIFER BAKER) writes:
>>What are some of the security measures to consider when dealing with 
>>WIRELESS LANS.


>1) Wireless LANS, at frequencies below 10GHz, are easy to monitor relatively
>cheaply. (At the 10Ghz range, one has to intercept the path of the microwave
>signal).
>Commercial receivers are available that will happily monitor any frewuency
>up to about 950 Mhz - If a TNC (with modem chip set for the correct baud rate)
>is then connected in to a PC, packets received can be decoded and analysed
>very easily.

The 950 Mhz one that we have tested is a spread spectrum implementation
with a setable frequency spread (to avoid the case of either accidental 
or purposeful interference from an identical box). In that particular 
case, I don't see any more security problems than with a normal Ethernet
(which in and off itself is a less than secure medium!.
	Spread spectrum, (for those of you who have never heard of it) is
a military invention that spreads the transmitted power out over a large
number of different frequencies (a little of the total power on each
frequency) which makes it hard to jam, and somewhat harder to monitor (in order
to get a decent signal level, the receiver needs to know all the frequencies
in use). In this particular application, it provides security (as noted above)
from a person with a single freq receiver, and probably as importantly,
resistance to interference, and the capability of having several units
operating independently (on different frequency spreads) near each other.


Peter Van Epp / Operations and Technical Support 
Simon Fraser University, Burnaby, B.C. Canada

jon_care@hicom.lut.ac.uk writes:

> 1) Wireless LANS, at frequencies below 10GHz, are easy to monitor relatively
> cheaply. (At the 10Ghz range, one has to intercept the path of the microwave
> signal).

Yes and no. There are LANs operating at 23 GHz that transmit an omni-directional
signal. As you increase frequency it is easier to narrow the beamwidth of a
point-to-point link, however a wireless LAN by definition wants wide area
coverage, not PTP. Even fixed PTP links are easy to intercept.

> Commercial receivers are available that will happily monitor any frewuency
> up to about 950 Mhz - If a TNC (with modem chip set for the correct baud rate)
> is then connected in to a PC, packets received can be decoded and analysed
> very easily.

Well, sort of. This isn't your basic 1200 bps AX.25 packet radio that you find
on 145.01. The 900 MHz systems all run spread spectrum. To intercept a signal
you require the same brand of LAN transciever (or at least one that uses the
same modulation encoding scheme), and you must then determine which particular
spreading code is being used. The former is relatively easy due to the limited
number of products currently available. The latter can be dealt with using a
brute force approach if you're patient.

> An answer to this could be to use some form of publickey encryption.

This is the obvious solution, and a good one. I'm curious why more vendors
don't provide this. Is it simply due to the silly DES export restrictions?

--lyndon

In article <jenn_b.5@aci_1.aci.ns.ca> jenn_b@aci_1.aci.ns.ca (JENNIFER BAKER) writes:
   What are some of the security measures to consider when dealing with 
   WIRELESS LANS.

Well, the usual questions concern issues like 
	- how sensitive is your data?
	- what kinds of threats are you worried about?
		(including, e.g., who's listening, how good are they, 
		loss-of-service?  jamming?  interference?)
	- how far are you broadcasting?
	- how near are your neighbors
	- how fast is your data rate?
	- what's on the LAN?  email only?  telnet with passwords?  NFS?

If you want a product plug, AT&T / NCR's WaveLAN product uses
spread-spectrum radio, which is hard to intercept and relatively
tolerant of noise and other LANs in the same area,
and offers an optional DES encryption chip (US only, I assume)
to provide much better security.  I forget the bit rate,
but it's about 2 mb/s, and the PC plugin cards emulate the standard 
PC Ethernet cards, so it's protocol-transparent, just a bit slower.
I think the range is around 200-300 meters for broadcast and 
10 km for line-of-sight with a directional antenna.
Email me if you want more details; I'll try to find some product literature.
--
#				Pray for peace;      Bill
# Bill Stewart 908-949-0705 wcs@anchor.att.com AT&T Bell Labs 4M312 Holmdel NJ
# Nov 12 - Anniversary of Indonesian massacre in East Timor, 1991
# Indonesia first invaded in 1975, and about 1/3 of the people have been killed.

In article <WCS.92Nov5231548@rainier.ATT.COM>, wcs@anchor (Bill Stewart +1-908-949-0705) writes:
>If you want a product plug, AT&T / NCR's WaveLAN product uses
>spread-spectrum radio, which is hard to intercept and relatively
>tolerant of noise and other LANs in the same area,
>and offers an optional DES encryption chip (US only, I assume)

Just a comment about semantics .. it hardly makes sense to talk about
"US only" encryption devices, since it is the USA who has the export
and use restrictions (via export laws, software patents and apparently
by control of law in the future), not the rest of the world.  You
probably mean "not to be exported from USA", assuming you are talking
about U.S. companies.

There are several DES chip and device manufacturers in Europe who are
glad to sell and glad about increased sales due to the export
restrictions.

//Jyrki

In article <1992Nov6.085140.18307@nntp.hut.fi> jkp@cs.HUT.FI (Jyrki Kuoppala) writes:
>In article <WCS.92Nov5231548@rainier.ATT.COM>, wcs@anchor (Bill Stewart +1-908-949-0705) writes:
>>If you want a product plug, AT&T / NCR's WaveLAN product uses
>>spread-spectrum radio, which is hard to intercept and relatively
>>tolerant of noise and other LANs in the same area,
>>and offers an optional DES encryption chip (US only, I assume)

>Just a comment about semantics .. it hardly makes sense to talk about
>"US only" encryption devices, since it is the USA who has the export
>and use restrictions (via export laws, software patents and apparently
>by control of law in the future), not the rest of the world.  You
>probably mean "not to be exported from USA", assuming you are talking
>about U.S. companies.

Minor quibble.  It's not *just* the US.  Any country which is a signatory
to the COCOMM treaty (which will include most of NATO, much of Europe
and many other countries) has to respect US export regulations.  Ie:
Canadian companies had to submit applications to COCOMM (via the dept of
External Affairs) for the export of certain technologies, including DES.

>There are several DES chip and device manufacturers in Europe who are
>glad to sell and glad about increased sales due to the export
>restrictions.

Depending on which country they're in, it may be illegal for them to
export it too.  However, as long as they don't export it, they'll
not have difficulties with US Export regulations or COCOMM treaties,
and they'll reap the sales benefit of not having to compete with the US
or any other COCOMM country.