EAP Overview

(Extensible Authentication Protocol)

Team Golmaal:

Vaibhav Sharma Vineet Banga

Manender Verma

Lovejit Sandhu

Abizar Attar

Contents:• Introduction

• Architecture

• Features

• Implementations

– Cisco LEAP– EAP-TLS– EAP-MD5– PEAP– Other Subtypes

• Comparison Chart

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Introduction

• What is EAP?– Defined by RFC 2284 and 3748– Universal Authentication Framework– Mainly used in Wireless Networks and Point to

point connections– A flexible protocol used to carry arbitrary authentication

information.– Typically rides on top of another protocol such as 802.1x

or RADIUS

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EAP Architecture

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EAP Features• Provides some common functions and a negotiation of the desired

authentication mechanism called methods.

• Currently there are about 40 different methods

• Methods defined in IETF RFCs include – EAP-MD5 – EAP-OTP– EAP-GTC– EAP-TLS– EAP-IKEv2 and in addition a number of vendor specific methods and new

proposals exist

• Commonly used modern methods capable of operating in wireless networks include EAP-TLS, EAP-SIM, EAP-AKA, PEAP, LEAP and EAP-TTLS

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Cisco LEAP• Lightweight Extensible Authentication Protocol also known

as Cisco-Wireless EAP

• Proprietary wireless LAN authentication method developed by Cisco Systems.

• Provides username/password-based authentication between a wireless client and a RADIUS server like Cisco ACS or Interlink AAA

• Among a few protocols used with the IEEE 802.1X standard for LAN port access control.

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Architecture of LEAP

Access Point

ClientACS Server

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LEAP Process

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Limitations of LEAP

• Uses a modified authentication protocol version of MS-CHAP in which user credentials are not strongly protected.

• Can be susceptible to eavesdropping.• For more robust implementations use of

cryptography is necessary for securing user credentials

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ASLEAP

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Cisco’s Response to Limitation of LEAP

• Suggests that network administrators to have either of the two reactive techniques:

– Force users to have stronger, more complicated passwords

– Switch to alternative protocol developed by Cisco (EAP-FAST) for more security.

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EAP TLS

• An Internet Engineering Task Force (IETF) standard (RFC 2716) that is

based on the TLS protocol (RFC 2246) • Considered extension to SSL

• Uses digital certificates for both user and server authentication • It uses PKI to secure communication to the RADIUS authentication server • EAP-TLS is the original standard wireless LAN EAP authentication protocol • Supported my all operating systems and network appliances.

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EAP Authentication Process in wireless network

EAP-TTLS (Extension of EAP-TLS)

• Extends EAP-TLS

• Securely tunnels Client authentication within TLS records

• TTLS requires only server-side certificates but in EAP TLS more certificates are used

• These certificates are used for one-way TLS authentication (network to user), and once you have a nice, safe, encrypted and integrity-checked channel, you can use EAP inside of the TLS tunnel for any other authentication

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PEAP• PEAP is an IETF draft RFC authored by Cisco Systems, Microsoft, and RSA

Security • A method to securely transmit authentication information, including

passwords, over wired or wireless networks• Uses a digital certificate only for server authentication• Very similar to TTLS! • A TLS tunnel is established, and another EAP session takes place inside• For user authentication, PEAP supports various EAP-encapsulated

methods within a protected TLS tunnel • PEAP sub-types - PEAPv0/EAP-MSCHAPv2 - PEAPv1/EAP-GTC

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PEAP authentication process

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EAP MD5• One of the most simple EAP types that can be used. Uses MD5

hashing.

• EAP-MD5 offers no key management or dynamic key generation, requiring the use of static WEP keys

• Okay for wired LANs, offers minimal security in wireless

• Vulnerable to dictionary attacks, and does not support mutual authentication or key generation

• Unsuitable with dynamic WEP, or WPA/WPA2 enterprise

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Other EAP Subtypes• EAP-PSK: pure symmetric-key EAP• EAP-IKEv2: EAP authentication method based on the Internet Key

Exchange Protocol version 2 (IKEv2) • EAP-FAST: Flexible Authentication via Secure Tunneling (it is a proposal by

Cisco Systems to fix the weaknesses of LEAP) • EAP-SIM: Used for authentication and session key distribution using the

Global System for Mobile Communications (GSM) Subscriber Identity Module (SIM)

• EAP-AKA: It is for UMTS Authentication and Key Agreement is used for authentication and session key distribution using the Universal Mobile Telecommunications System (UMTS)

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EAP-MD5 LEAP EAP-TLS EAP-TTLS PEAP

ServerAuthentication

None Password Hash Public Key (Certificat

e)

Public Key (Certificat

e)

Public Key (Certificat

e)

SupplicantAuthentication

Password Hash Password Hash Public Key(Certificate or

Smart Card)

CHAP, PAP, MS-CHAP(v2),

EAP

Any EAP, like EAP-MS-

CHAPv2 or Public Key

Dynamic Key Delivery

No Yes Yes Yes Yes

Security Risks Identity exposed, Dictionary

attack, Man-in-

the-Middle (MitM) attack, Session

hijacking

Identity exposed, Dictionary

attack

Identity exposed

MitM attack MitM attack; Identity

hidden in Phase 2

but potential exposure in Phase 1

Comparison Chart

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References• http://en.wikipedia.org/wiki/Extensible_Authentication_Protocol

• http://www.wifiplanet.com/tutorials/article.php/3075481

• http://wireless.utk.edu/documentation/papers/802.1x-chris.pdf

• http://www.cisco.com/en/US/netsol/ns339/ns395/ns176/ns178/networking_solutions_white_paper09186a008009c8b3.shtml

• http://searchnetworking.techtarget.com/originalContent/0,289142,sid7_gci843996,00.html

• http://asleap.sourceforge.net

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