Life After WPALife After WPA

Yap Chern NamYap Chern NamSecretary of IEEE Secretary of IEEE Computer ChapterComputer Chaptercnyap@tp.edu.sgcnyap@tp.edu.sg

OverviewOverview

What has happened?What has happened? What is going on now?What is going on now? What is up and coming?What is up and coming?

Why WPA/802.11i?Why WPA/802.11i? – Walker, “Unsafe at any Key Size” , IEEE

802.11 doc. 00-362, October 2000 – Arbaugh, “An inductive Chosen Plaintext

Attack against WEP”, IEEE 802.11 doc. 01-230, May 2001

– Borisov, Goldberg, Wagner, “The insecurity of 802.11”,Proceedings of International Conference on Mobile Computing and Networking, July 2001

– Fluhrer, Mantin, Shamir, “Weaknesses in the key schedule algorithm of RC4”, Proceedings of 4th Annual Workshop of Selected Areas of Cryptography, August 2001

How are the Hackers?How are the Hackers?

http://http://www.youtube.com/watch?vwww.youtube.com/watch?v=kDD9PjiQ2_U&feature==kDD9PjiQ2_U&feature=player_embeddedplayer_embedded

Is WPA Safe?Is WPA Safe?

2008, Martin Beck / Erik Tews2008, Martin Beck / Erik Tews• Dictionary Attacks on TKIPDictionary Attacks on TKIP

2009, Masakatu Morii, Toshihiro 2009, Masakatu Morii, Toshihiro • (Reduce under 1 minute)(Reduce under 1 minute)

WPA2 too complex?WPA2 too complex?

Windows 2003 Server;Windows 2003 Server; Windows 2008 ServerWindows 2008 Server

• PEAP/MS-CHAPPEAP/MS-CHAP• Server AuthenticationServer Authenticationhttp://www.microsoft.com/downloads/http://www.microsoft.com/downloads/

details.aspx?familyid=0f7fa9a2-e113-details.aspx?familyid=0f7fa9a2-e113-415b-b2a9-415b-b2a9-b6a3d64c48f5&displaylang=enb6a3d64c48f5&displaylang=en

Low Cost Solutions - Zero ShellLow Cost Solutions - Zero Shell

Voice over IPVoice over IP

2009,"It only took more than 125 2009,"It only took more than 125 years but POTS (plain old telephony years but POTS (plain old telephony service) is now on the decline in the service) is now on the decline in the U.S.," said U.S.," said Ken Dulaney, vice Ken Dulaney, vice president and distinguished analyst president and distinguished analyst at Gartnerat Gartner. "The emergence of VoIP . "The emergence of VoIP and the phenomenal rise of the and the phenomenal rise of the mobile phone now represent the 'dial mobile phone now represent the 'dial tone' for the future" tone' for the future"

IEEE 802.11 SecurityIEEE 802.11 Security

Authentication (Request)

Authentication (Success)

Authentication (Request)

Authentication (Challenge)

Authentication (Response)

Authentication (Success)

Open System Authentication +Re-association

Shared Key Authentication +Re-association

Re-association Request

Re-associationResponse

Re-associationRequest

Re-associationResponse

Mobile Station

Access Point

Mobile Station

Access Point

IEEE 802.1x (EAP/TLS)IEEE 802.1x (EAP/TLS)

EAPOL-Start

EAP Rq (ID)

EAPOL Rs (ID)

EAP-Start

EAPOL Rq (ID)

EAP Rs (ID)

EAP TLS-StartEAPOL TLS-Start

TLS Client HelloTLS Client Hello

TLS Server HelloTLS Server Hello

EAPOL TLS FinishedEAP TLS Finished

EAPOL SuccessPMK Res

Mobile Station / Supplicant

Access Point / Authenticator

RADIUS / Authentication

Server

4 Way Handshake Mutual 4 Way Handshake Mutual AuthenticationAuthentication

EAPOL (key-info, S-nonce, MIC, RSN-IE)

EAPOL (key-info, A-nonce, MIC, RSN-IE)

EAPOL (key-info, MIC)

EAPOL (key-info, A-nonce)

Mobile Station / Supplicant

Access Point / Authenticator

IEEE 802.11e - 2005IEEE 802.11e - 2005

ADDTS request

ADDTS response

Mobile Station / Supplicant

Access Point / Authenticator

BSS TransitionBSS Transition

Data

Ack

Roaming Connection

Roaming Success

Mobile Station Access Point A Access Point B

Data

Ack

Data

Lo

ss and

Tim

ing

du

ring T

ran

sition

Con

nection

P

rocess

Dete

rmin

e Sig

nal L

oss &

S

cann

ing fo

r New

AP

Scanning State

Losing Connection

Security or Voice?Security or Voice?Mobile Station

Access Point / Authenticator

Authentication Server

EAPOL Start

EAP Start

EAP Success – PMK Res

EAPOL Success

EAPO

L

RADI

USMessage D

Message A

Message B

Message C

ADDTS Req

ADDTS Res

Mutual Authenti-

cation

QoS Spec

Mutual Authentication

· Message A = key_info, Anounce

· Message B = key_info, Snounce, MIC, RSE_IE

· Message C = key_info, Anonce, MIC, RSE_IE

· Message D= key_info, MIC

Open SystemAuth

Open SystemAuth

Re-assoc Req

Re-assoc Res

Upper Layer

Authenti-cation

Network SetupNetwork Setup

W2K3R1

S1

AP1

AP2

VG1

STA

CTR1

Voice Traffic on BSS TransitionVoice Traffic on BSS Transition

0.00

2.00

4.00

6.00

8.00

10.00

12.00

1 2 3 4 5 6 7 8 9 10

Trials

Sec

on

ds

WPA2 Clear

Various Codec on Wireless LANVarious Codec on Wireless LAN

0.0010.0020.0030.0040.0050.0060.0070.0080.0090.00

5 10 15 20 25 30 35 40 45 50

Num of Voice Call

Per

cen

t P

kt L

oss

G711.1 G711.2 G723.1 G729.2 G729.3

IEEE 802.11k - 2008IEEE 802.11k - 2008

Load Balancing in WLANLoad Balancing in WLAN Capacity ManagementCapacity Management

Roaming becomes more inportantRoaming becomes more inportant

IEEE 802.11r - 2008IEEE 802.11r - 2008

New IEEE 802.11rMessage Sequence Diagram

Mobile StationAccess Point / Authenticator

Authentication Server

Open SystemAuth

Open SystemAuth

IEEE 802.11rRe-assoc Req

Auth Info

Auth InfoIEEE 802.11rRe-assoc Res

New Message D

Message B and

ADDTS Req

Message C and

ADDTS Res

OPNET SimulationOPNET SimulationRoaming Timing with w/o STA Load

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

0 50 100 150 200 250

BackEnd Latency (mSec)

Roaming Latency (Sec)

IEEE 802.11i Roaming Latency IEEE 802.11i Voice Latency

IEEE 802.11r Roaming Latency IEEE 802.11r Voice Latency

Current SecurityCurrent Security

Management Frame and Control are Management Frame and Control are Clear text.Clear text.

Why so worry so much for Why so worry so much for management frames??....management frames??....

IEEE 802.11k lots of network IEEE 802.11k lots of network information related information, information related information, handoff information handoff information

De-Auth and Dis-Assoc simplest DoSDe-Auth and Dis-Assoc simplest DoS

IEEE 802.11w - 2009IEEE 802.11w - 2009

802.11w get rids of “Spoofed 802.11w get rids of “Spoofed Disconnect” DoS attacksDisconnect” DoS attacks• Deauthentication Deauthentication • DisassociationDisassociation

Certain “Action Management Certain “Action Management Frames” are made anti-spoof Frames” are made anti-spoof • Spectrum Management (IEEE 802.11k)Spectrum Management (IEEE 802.11k)• QoS (IEEE 802.11e)QoS (IEEE 802.11e)• Fast BSS Transition(IEEE 802.11r)Fast BSS Transition(IEEE 802.11r)

How is it done?How is it done?

IEEE 802.11w adds cryptographic IEEE 802.11w adds cryptographic protection to Deauth and Disassocprotection to Deauth and Disassoc• Using MIC attached to the Management Using MIC attached to the Management

Frames.Frames.

Thank YouThank You