Securing Wireless Part 1 of 2

Table of Contents

Securing 802.11x Networking ...... 2

802.11 Version Comparisons ...... 3

Service Sets ...... 10

Wireless Security Evolution -1 ...... 12

Wireless Security Evolution -2 ...... 15

Wireless Security Evolution -1 ...... 16

Wireless Security Evolution -2 ...... 17

Wireless Security Evolution -3 ...... 18

Wireless Security Evolution -4 ...... 19

Notices ...... 20

Page 1 of 20 Securing 802.11x Networking

Securing 802.11x Networking

802.11x Comparison 802.11x Service Sets 802.11x Wireless Security Evolution WEP, 802.1X, WPA, WPA2 Best Practices for Securing 802.11x

**031 Joe Mayes: Alright so now let's look at securing 802.11 networking. And 802.11 is, what do we more commonly call it?

Student: Wi-Fi.

Joe Mayes: Wi-Fi, right? Alright so securing Wi-Fi. We're going to compare different 802.11 types. We're going to talk about service set types, wireless security evolutions, and best practices.

Page 2 of 20 802.11 Version Comparisons

802.11 Version Comparisons

802.11b 802.11g 802.11a 802.11n

2.4 GHz – DSSS 2.4 GHz – OFDM 5 GHz – OFDM 2.4GHz / 5 GHz

11, 5.5, 2, 1 Mbps Up to 54 Mbps Up to 54 Mbps Up to 600Mbps throughput throughput throughput

Range: 200 Ft. Range: 200 ft. Range: 80 ft. Range: depends on indoors; 1000 ft. indoors; 1000 ft. indoors; 500 ft. frequency (matches outdoors outdoors outdoors 802.11a and g)

High Interference High Interference Low Interference Depends on potential potential potential frequency (matches 802.11a and g)

Most Widely Backwards Not Compatible Compatible with all deployed, but Compatible with b with b or g other protocols becoming obsolete

**032 This doesn't have all the 802.11 types. It has all the popular ones in use right now. If you were to make one more column up here, we'll see in the future that 802.11ac will become more popular in the future. It's just barely been released and very few devices use it at this point; 802.11ac is not on the list. However the ones we are mainly concerned about are the ones that most people are going to be using so we'll talk about these. 802.11 was actually if you were to go all the way to the left-hand side, there is actually an 802.11 that was before 802.11b. The 802.11 was the original, original, original version of 802.11 and it only

Page 3 of 20 went with one and two megabits and it got replaced by 802.11b fairly early on.

So we don't find many devices that are actually 802.11 anymore. The trick is 802.11b, 802.11g, 802.11a, and 802.11n are all backward compatible to guess what? All the way back to the original 802.11. So some things we talk about will be for backward compatibility. For instance on the 802.11b, it operates a 2.4 gigahertz; 2.4 gigahertz happens to be in the ISM band. Anybody know what the ISM band is?

Student: Communications?

Student: Scientific network? No.

Joe Mayes: Yeah, instrumentation, scientific, and medical. It's basically an unlicensed spectrum band and that way we don't all have to have licenses just to run our wireless access points in our homes, right, is the idea behind it. It operates 2.4 gigahertz. It operates in direct sequence spread spectrum which basically means if it took this much bandwidth to send the signal, it uses this much instead. And the reason it does that is right here.

Has anybody ever heard the term "You should buy land because they're not making any more of it."? Anybody heard that one? You can always buy land because they're not making any more of it. Well the same problem with radio frequencies, right? There's only so many radio

Page 4 of 20 frequencies we have to use and there is a lot of juggling around and very bitter battles over who is going to get what spectrum. And in the U.S. we made a lot of changes in that. What was the last huge change we made in spectrum allocation?

Student: Analog to digital TV.

Joe Mayes: Analog to digital in TV didn't just convert it from analog to digital. It also did what?

Student: Eliminated analog?

Student: Freed up a boatload of--

Joe Mayes: Yeah they actually moved the spectrum, they actually moved to a different set of frequencies for digital television and freed up the 400 and 600 megahertz bandwidths for they were formerly owned by low band and high band VHF, channels 2 to 13. So in this model, if I've got a spectrum here that's roughly 2.4 gigahertz, okay? If I have a narrowband transmitter, what's a narrowband transmitter going to look like on a spectrum analyzer? It's going to be this type of looking thing, right? If I have a broadband like I'm sorry direct sequence spread spectrum, a spread spectrum, I don't know why I have trouble with that, a spread spectrum signal in the same frequency range, it will look like this.

And because of that those two can operate together. The narrow band receiver will see the spread spectrum

Page 5 of 20 signal as noise, right? Because it doesn't have enough signal strength to get out of the noise realm. Because the narrowband receiver is going to be just listening up here to the top. The spread spectrum receiver however, listens across the entire beam width from here to here, and therefore it sees the narrowband transmitter as interference. But it can transmit through the interference because it's clear on all the sides and it can still see that broad spectrum signal rays. Is there a third type of signal that can be in here? Somebody say "yes".

Student: Yes.

Joe Mayes: Okay, cool. What's the third type?

Joe Mayes: So if this is, I want to label these. If this is narrowband and if this one down here is spread spectrum, what's the third type?

Student: Direct sequence spread spectrum.

Joe Mayes: Well that's what this one is, right? How about... What did I just try to draw?

Student: Channels.

Student: RAM?

Student: Frequency hopping?

Joe Mayes: Right frequency hopping spread spectrum. Now, anybody know a frequency hopping spread spectrum 2.4 gigahertz technology?

Page 6 of 20 Student: Bluetooth.

Joe Mayes: Bluetooth. And what happens is all three of these can operate in the same band at the same time and not interfere with each other because each is listening for a different type of signal. Does that make sense? Questions? So frequency hopping spread spectrum, direct sequence spread spectrum, and narrow band transmission.

So all of these operate on direct sequence spread spectrum; 802.11 operated on three types. They could be frequency hopping, direct sequence, or infrared if you can believe that. But they abandoned all that when they went to 802.11b and said let's just go with DSSS. So it operated at 11, 5, 2 and 1 megabits and the 2 and 1 were the original speeds of 802.11. That's why it's backwards compatible. You can see the ranges it has a high interference potential because it covers such a broad spectrum and it's very widely deployed but becoming obsolete. And 802.11g also operates at 2.4 gigahertz, but it uses orthogonal frequency division multiplexing. Everybody say that three times fast, right? Orthogonal frequency division multiplexing. What's going on when you look across the top at any of these technologies is they keep changing the encoding. What's the difference between encoding and encryption?

Student: Keys.

Page 7 of 20 Joe Mayes: Encoding and encryption.

Student: Encoding is just the way it's sent.

Joe Mayes: Right.

Student: Encryption is trying to hide it.

Joe Mayes: Right in encryption we're trying to take plain text and hide it, turn it into ciphertext, right? In encoding, we're just trying to find a way to place ones and zeroes digital ones and zeroes on an analog carrier. What's going to be a one on a radio wave, right? And they keep changing the definition of what constitutes a one and zero. And the reason they keep changing the definition is the smarter they make the definition, the more ones and zeroes they can put in the same space. The more ones and zeroes they put in the same space, what happens?

Student: The faster it is.

Joe Mayes: Faster your data rate is. So when they went to DSSS to OFDM over DSSS the data rate went from 11 megabits a second to 54 megabits a second. They found a way encode more ones and zeroes. Because encoding isn't about hiding them. Encoding is about how to carry more of them. So 802.11b and g are both on 2.4 gigahertz; 802.11a operates in the 5 gigahertz band. And what that means is if you have trouble-- what

Page 8 of 20 are the other things that operates a 2.4 gigahertz?

Student: Microwave.

Joe Mayes: Microwave ovens. Telephones and other things are all pretty well behaved. Baby cameras are not well behaved, microwave ovens are not well behaved. So because of those problems, there was a move to move everybody up, everybody possible up to 5 gigahertz to get away from that. The problem is the 5 gigahertz range they chose has its own issues which is that 5 gigahertz range operates in the same range as European weather radar. And as the same range as aircraft radar.

So when they started to move up in that range, they had to write the protocol such that if an access point hears a radar transmission, it has like 40 microseconds to move to another frequency so that it doesn't jam the radar, because radar and safety of airplanes landing wins over whether you get to cruise the internet or not. So the versions all operate on basically the same two bandwidths, either 2.4 gigahertz or 5. The data rates can go up to 600 megabits a second. Their range varies and what happens is their range varies kind of depending on what data rate you want. When you get far enough away from them, the data rates slow down.

Page 9 of 20 Service Sets

Service Sets

Independent Basic Service Set (IBSS) • Ad-hoc: wireless clients talk only to other wireless clients Infrastructure Basic Service Set • Infrastructure: clients send all packets to one Access Point (AP) — AP acts as bridge into wired network Infrastructure Extended Service Set • Seamless transition not guaranteed by 802.11 • Generally requires use of Mobile IP Service Set Identifiers (SSID) • Used by vendors to uniquely identify a network

**033 So, service sets. Service sets have to do with 802.11 itself. The last slide we were talking about, when we talked about frequencies, that's just radio energy, right? Just radio wave energy. In service sets, we have an independent basic service set and the infrastructure basic service set, an infrastructure extended service set, and a service set identifier. Is that exciting or what? What it really means independent basic service set and IBSS, that's the ad hoc system. What's an ad hoc system? Anybody ever taken their laptop or anything to the airport? And they see "Free Wi- Fi" but instead of a picture of an

Page 10 of 20 access point there's a picture of a laptop there in the little icon? What happens is that's somebody's individual laptop trying to get you to hook onto it to go to the internet. If you buy that and hook on, what's going to happen?

Joe Mayes: Yeah you are now connected to somebody else's laptop, they are now connected to you. They can either pull your data directly or if they are smart and on the other side they've got one of those Verizon MiFi cards, they can just pass all your traffic through the laptop. You will never know that they are sniffing everything you do. So an infrastructure basic service set, that's an AP, access point. An infrastructure extended service set, that is a network of access points.

What happens around here, let's say we've got 20 different access points in this building and they all use the same SSID and they are all connected on the same network, they can all talk to each other. That's an extended service set and what it means is you can roam. What's roaming? You can walk from one part of the building to the other part and you go from AP to AP. The connection doesn't break. And ultimately service set identifier or the SSID, that's the name you see for a wireless network, right?

Page 11 of 20 Wireless Security Evolution -1

Wireless Security Evolution -1

Sep 1999: Wired Equivalent Privacy (WEP) • Referred today as Static or Manual WEP • RC4 stream cipher — 64-bit WEP: 40-bit key + 24-bit initialization vector (IV) — 128-bit WEP: 104-bit key + 24-bit IV — Does not include a key management protocol o Single key shared amongst users — Aug 01: passive attack on WEP’s use of RC4 and IV — 2005: group within FBI cracks 128-bit WEP in 3 minutes • CRC-32 checksum

**034 So security of all this wireless stuff. Originally we had WEP, Wired Equivalent Privacy. And that's really not a bad name for it because are wired connections secure? No. Can I sniff a wired connection? Sure I can.

Student: It's harder.

Joe Mayes: Not very much harder. Anybody know this term, "inductive pickup loop"?

Student: Uh-hum.

Joe Mayes: What is an inductive pickup loop?

Page 12 of 20 Student: Just what's over the cable.

Joe Mayes: Right it's like an antenna you can loop over a cable and then you pick up the changes in the electromagnetic signals going through the cable which allows you to read the data going through the cable. They use them. One of the places you can go see them any time of the day now is if you go to most auto stores and you are having trouble with your battery starting, they will throw this little clamp over your battery cable and tell you to start the car and they'll tell you how many amps it took to run the starter. That's an inductive pickup loop. All you need is a little less coarse grain one to be able to see what's going on in the network wire. So wired equivalent privacy is not a bad name for it. That's also why, by the way if you have SIPRNet can you ever put it in a wire? Can you ever run secure networking on a wire on a cable wire?

Student: I'm misunderstanding the question because most--

Student: You mean wireless.

Joe Mayes: No can you put SIPRNet on a wired connection?

Student: Yes.

Student: You have to.

Joe Mayes: Yes but what? If it's on a wire connection, the wires have to be exposed where you can see it and

Page 13 of 20 see that they are not being tapped. If they go in walls, then they can be in?

Joe Mayes: Fiber optic.

Student: It came from the walls.

Student: Or they convert it to fiber optic before they go into the wall.

Joe Mayes: Right.

Student: To a converter box.

Joe Mayes: Yeah you have to convert it to fiber optics before you can put in a hidden state. Joe Mayes: You also have to monitor the conduit as you put them in. But as far as the wire side goes, the only time you can actually use a physical wire is when you can see that there's no inductive pickup loops on it.

Student: Right.

Joe Mayes: Fiber optics since it doesn't have that problem, they allow it to do other things. So wired equivalent privacy. They used RC4 stream cipher. They used a 40-bit key and we can figure out from those things how secure does this actually look like. Shared single password among all the users. They all have the same key. And by 2005 the FBI was cracking 128-bit WEP in three minutes. Not very secure, right?

Page 14 of 20 Wireless Security Evolution -2

Wireless Security Evolution -2

2001: IEEE 802.1X Port-based Network Access Control • IEEE adaptation of IETF’s Extensible Authentication Protocol (EAP) specified in RFC 2284 and updated by 3748 • Dynamically distributes keys for APs and client stations

Authentication Supplicant Authenticator Server EAPOL EAP Method RADIUS EAP

802.1X 802.1X RADIUS RADIUS UDP/IP UDP/IP 802.11 802.11 802.3 802.3

**035 So next stage of the game was let's go to--

Page 15 of 20 Wireless Security Evolution -1

Wireless Security Evolution -1

**034 And by the way this had a huge impact on the commercialization of wireless. Corporations that wanted to go wireless wouldn't go wireless until the people did something better than WEP which motivated all the manufactures to say yeah, we can fix that.

Page 16 of 20 Wireless Security Evolution -2

Wireless Security Evolution -2

Authentication Supplicant Authenticator Server EAPOL EAP Method RADIUS EAP

802.1X 802.1X RADIUS RADIUS UDP/IP UDP/IP 802.11 802.11 802.3 802.3

**035 So they came up with an interim solution. The interim solution included things like using 802.1X; 802.1X is the port-based access control where you plug a cable into a switch and you have to authenticate before the switch port will turn on. They took the exact same concept and said before you can connect to an access point, you have to authenticate. So you have to have authenticated access to an access point. So that's 802.1X used in wireless.

Page 17 of 20 Wireless Security Evolution -3

Wireless Security Evolution -3

Apr 2003: Wi-Fi Protected Access (WPA) • Wi-Fi Alliance implementation of IEEE’s draft 3.0 of 802.11i • Enterprise Mode WPA — 802.11i specifies use of 802.1X port management — Per user authentication requiring an authentication server (RADIUS) • Personal Mode WPA — Pre-Shared Key (PSK) authentication — Designed for simplicity of deployment, but passphrases < 20 characters are vulnerable to a password cracking attack (e.g. WPA Cracker) • WPA Implements Temporal Key Integrity Protocol (TKIP) — Designed to allow continued use of WEP’s RC4 hardware — Dynamically changes encryption keys as system is used — Uses Michael, an improved Message Integrity Check algorithm — Authentication via WPA-PSK or 802.1X EAP method

**036 Then they came up with Wi- Fi Protected Access. And Wi-Fi protected access is a draft of what became the 802.11i standard. Wi-Fi protected access is a label used by the Wi-Fi Alliance which is an industry group that standardizes manufacturing and interoperability so they adopted WPA and put it on their devices. You can still use WPA today. The problem is WPA wasn't the adopted standard. WPA has a couple weaknesses you can use. It uses temporal key integrity protocol and still used RC4 for an encryption. Those were thought to be not strong enough so that draft of the 802.11i standard was never adopted.

Page 18 of 20 Wireless Security Evolution -4

Wireless Security Evolution -4

Sept 2004, Wi-Fi Protected Access 2 (WPA2) • Implements mandatory elements of IEEE 802.11i (Jun 2004) — certified by Wi-Fi Alliance • WPA2 implements Counter Mode with Cipher Block Chaining Media Authentication Code Protocol (CCMP) — Built around AES block-cipher — Handles encryption, key management, and message integrity • Backward compatible with WPA products using TKIP • Not compatible with older WEP-oriented (RC4) hardware

**037 They adopted a bigger standard or a heavier duty standard. That heavier duty standard became 802.11i final and also became WPA2 because they didn't want to walk away from WPA so instead they said let's support WPA and we'll support the final standard and we'll call it WPA2. And the differences are it's built around AES instead of RC4. So RC4 stream cipher and instead they went to AES block-cipher. And the reason that became an issue initially was a lot the equipment that was built didn't have a chip or a capability to run AES so when they converted it

Page 19 of 20 to WPA2, it was a painful conversion for a lot of companies. They had to go out and buy all new hardware.

Notices

© 2014 Carnegie Mellon University This material is distributed by the Software Engineering Institute (SEI) only to course attendees for their own individual study. Except for the U.S. government purposes described below, this material SHALL NOT be reproduced or used in any other manner without requesting formal permission from the Software Engineering Institute at [email protected]. This material was created in the performance of Federal Government Contract Number FA8721-05-C-0003 with Carnegie Mellon University for the operation of the Software Engineering Institute, a federally funded research and development center. The U.S. government's rights to use, modify, reproduce, release, perform, display, or disclose this material are restricted by the Rights in Technical Data-Noncommercial Items clauses (DFAR 252-227.7013 and DFAR 252-227.7013 Alternate I) contained in the above identified contract. Any reproduction of this material or portions thereof marked with this legend must also reproduce the disclaimers contained on this slide. Although the rights granted by contract do not require course attendance to use this material for U.S. government purposes, the SEI recommends attendance to ensure proper understanding. THE MATERIAL IS PROVIDED ON AN “AS IS” BASIS, AND CARNEGIE MELLON DISCLAIMS ANY AND ALL WARRANTIES, IMPLIED OR OTHERWISE (INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE, RESULTS OBTAINED FROM USE OF THE MATERIAL, MERCHANTABILITY, AND/OR NON-INFRINGEMENT). CERT ® is a registered mark owned by Carnegie Mellon University.

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