Wireless LAN SecurityWireless LAN Security

CS391CS391

OverviewOverview

Wireless LAN TopologyWireless LAN Topology 802.11 Standards802.11 Standards Simple SecuritySimple Security WEPWEP 802.1x802.1x WPAWPA 802.11i802.11i

Wi-FiWi-Fi

Wi-Fi (short for “Wireless Fidelity") is the popular Wi-Fi (short for “Wireless Fidelity") is the popular term for a high-frequency wireless local area term for a high-frequency wireless local area network (WLAN)network (WLAN) Promoted by the Wi-Fi Alliance (Formerly WECA - Promoted by the Wi-Fi Alliance (Formerly WECA -

Wireless Ethernet Carriers Association) Wireless Ethernet Carriers Association)

Used generically when referring to any type of Used generically when referring to any type of 802.11 wireless networks, whether 802.11a, 802.11 wireless networks, whether 802.11a, 802.11b, 802.11g, dual-band, etc. The term is 802.11b, 802.11g, dual-band, etc. The term is promulgated by the Wi-Fi Alliancepromulgated by the Wi-Fi Alliance

Wi-FiWi-Fi

Wi-Fi standards use the Ethernet protocol and Wi-Fi standards use the Ethernet protocol and CSMA/CA (carrier sense multiple access with CSMA/CA (carrier sense multiple access with collision avoidance) for path sharing collision avoidance) for path sharing

The 802.11b (Wi-Fi) technology operates in the The 802.11b (Wi-Fi) technology operates in the 2.4 GHz range offering data speeds up to 11 2.4 GHz range offering data speeds up to 11 megabits per second. The modulation used in megabits per second. The modulation used in 802.11 has historically been phase-shift keying 802.11 has historically been phase-shift keying (PSK). (PSK). Note, unless adequately protected, a Wi-Fi wireless Note, unless adequately protected, a Wi-Fi wireless

LAN is easily accessible by unauthorized users LAN is easily accessible by unauthorized users

Wireless LAN TopologyWireless LAN Topology Wireless LAN is typically deployed as an extension of Wireless LAN is typically deployed as an extension of

an existing wired network as shown below.  an existing wired network as shown below. 

Wireless LAN TopologyWireless LAN Topology Here is an example of small business usage of Wi-Fi Here is an example of small business usage of Wi-Fi

Network.Network.

DSLConnection

Etc.

DSL Router

The DSL router and Wi-Fi AP are often

combined into a single unit

What is 802.11?What is 802.11?

802.11 refers to a family of specifications 802.11 refers to a family of specifications developed by the IEEE for wireless LAN developed by the IEEE for wireless LAN technology. 802.11 specifies an over-the-air technology. 802.11 specifies an over-the-air interface between a wireless client and a base interface between a wireless client and a base station or between two wireless clients. station or between two wireless clients.

The IEEE accepted the specification in 1997. The IEEE accepted the specification in 1997.

802.11 Family Members802.11 Family Members

There are several specifications in the 802.11 family: There are several specifications in the 802.11 family: 802.11802.11

Applies to wireless LANs and provides 1 or 2 Mbps Applies to wireless LANs and provides 1 or 2 Mbps transmission in the 2.4 GHz band using either transmission in the 2.4 GHz band using either frequency hopping spread spectrum (FHSS) or direct frequency hopping spread spectrum (FHSS) or direct sequence spread spectrum (DSSS). sequence spread spectrum (DSSS).

802.11a802.11a An extension to 802.11 that applies to wireless LANs An extension to 802.11 that applies to wireless LANs

and provides up to 54 Mbps in the 5GHz band. and provides up to 54 Mbps in the 5GHz band. 802.11a uses an orthogonal frequency division 802.11a uses an orthogonal frequency division multiplexing encoding scheme rather than FHSS or multiplexing encoding scheme rather than FHSS or DSSS. DSSS.

802.11 Family Members802.11 Family Members

802.11b802.11b (also referred to as 802.11 High Rate or Wi-Fi) is an (also referred to as 802.11 High Rate or Wi-Fi) is an

extension to 802.11 that applies to wireless LANs and extension to 802.11 that applies to wireless LANs and provides 11 Mbps transmission (with a fallback to 5.5, provides 11 Mbps transmission (with a fallback to 5.5, 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses 2 and 1 Mbps) in the 2.4 GHz band. 802.11b uses only DSSS. 802.11b was a 1999 ratification to the only DSSS. 802.11b was a 1999 ratification to the original 802.11 standard, allowing wireless original 802.11 standard, allowing wireless functionality comparable to Ethernet. functionality comparable to Ethernet.

802.11g802.11g Applies to wireless LANs and provides 20+ Mbps in Applies to wireless LANs and provides 20+ Mbps in

the 2.4 GHz band.the 2.4 GHz band.

802.11802.11

The newest IEEE standard in the Wi-Fi The newest IEEE standard in the Wi-Fi category is category is 802.11n802.11n. .

Designed to improve on 802.11g in the Designed to improve on 802.11g in the amount of bandwidth supported by utilizing amount of bandwidth supported by utilizing multiple wireless signals and antennas multiple wireless signals and antennas instead of one. 802.11n connections instead of one. 802.11n connections should support data rates of over 100 should support data rates of over 100 Mbps (up to 600Mbps). 802.11n alsoMbps (up to 600Mbps). 802.11n also

802.11n802.11n

offers somewhat better range over earlier offers somewhat better range over earlier Wi-Fi standards due to its increased signal Wi-Fi standards due to its increased signal intensity. 802.11n equipment will be intensity. 802.11n equipment will be backward compatible with 802.11g gear.backward compatible with 802.11g gear.

802.11 Standards

802.11 The original WLAN Standard. Supports 1 Mbps to 2 Mbps.

802.11a High speed WLAN standard for 5 Ghz band. Supports 54 Mbps.

802.11b WLAN standard for 2.4 Ghz band. Supports 11 Mbps.

802.11e Address quality of service requirements for all IEEE WLAN radio interfaces.

802.11f Defines inter-access point communications to facilitate multiple vendor-distributed WLAN networks.

802.11g Establishes an additional modulation technique for 2.4 Ghz band. Intended to provide speeds up to 54 Mbps. Includes much greater security.

802.11h Defines the spectrum management of the 5 Ghz band for use in Europe and in Asia Pacific.

802.11i Address the current security weaknesses for both authentication and encryption protocols. The standard encompasses 802.1X, TKIP, and AES protocols.

802.11 Authentication802.11 Authentication

The 802.11 standard defines several services that The 802.11 standard defines several services that govern how two 802.11 devices communicate. The govern how two 802.11 devices communicate. The following events must occur before an 802.11 station can following events must occur before an 802.11 station can communicate with an Ethernet network through a communicate with an Ethernet network through a wireless access point provides:wireless access point provides:

1.1. Turn on the wireless ClientTurn on the wireless Client

2.2. Client listens for messages from any access points (AP) that are Client listens for messages from any access points (AP) that are in rangein range

3.3. Client finds a message from an AP that has a matching SSIDClient finds a message from an AP that has a matching SSID

4.4. Client sends an authentication request to the APClient sends an authentication request to the AP

5.5. AP authenticates the stationAP authenticates the station

6.6. Client sends an association request to the APClient sends an association request to the AP

7.7. AP associates with the stationAP associates with the station

8.8. Client can now communicate with the Ethernet network thru the Client can now communicate with the Ethernet network thru the

APAP

What Exactly Is 802.1x?What Exactly Is 802.1x?

Standard set by the IEEE 802.1 working group.Standard set by the IEEE 802.1 working group. Describes a standard Describes a standard link layer protocollink layer protocol used for used for

transporting higher-level authentication transporting higher-level authentication protocolsprotocols..

Works between the Works between the SupplicantSupplicant (Client Software) (Client Software) and the and the AuthenticatorAuthenticator (Network Device). (Network Device).

Maintains backend communication to an Maintains backend communication to an Authentication (Typically RADIUS) ServerAuthentication (Typically RADIUS) Server..

What Does it Do?What Does it Do?

Transport authentication information in the form of Transport authentication information in the form of Extensible Extensible Authentication Protocol (EAP)Authentication Protocol (EAP) payloads. payloads.

The authenticator (switch) becomes the middleman for relaying The authenticator (switch) becomes the middleman for relaying EAP received in 802.1x packets to an authentication server by EAP received in 802.1x packets to an authentication server by using RADIUS to carry the EAP information.using RADIUS to carry the EAP information.

Several EAP types are specified in the standard.Several EAP types are specified in the standard. Three common forms of EAP areThree common forms of EAP are

EAP-MD5 – MD5 Hashed Username/PasswordEAP-MD5 – MD5 Hashed Username/PasswordEAP-OTP – One-Time PasswordsEAP-OTP – One-Time PasswordsEAP-TLS – Strong PKI Authenticated Transport Layer Security EAP-TLS – Strong PKI Authenticated Transport Layer Security (SSL)(SSL)

802.1x Header EAP Payload

What is RADIUS?What is RADIUS? RADIUS – The RADIUS – The RRemote emote AAuthentication uthentication DDial In ial In UUser ser SServiceervice A protocol used to communicate between a network device A protocol used to communicate between a network device

and an authentication server or database.and an authentication server or database. Allows the communication of login and authentication Allows the communication of login and authentication

information. i.e. Username/Password, OTP, etc. using information. i.e. Username/Password, OTP, etc. using Attribute/Value pairs (Attribute/Value pairs (Attribute = ValueAttribute = Value))

Allows the communication of extended attribute value pairs Allows the communication of extended attribute value pairs using “Vendor Specific Attributes” (VSAs).using “Vendor Specific Attributes” (VSAs).

Can also act as a transport for EAP messages.Can also act as a transport for EAP messages. RFC2865, RFC2866 and othersRFC2865, RFC2866 and others

RADIUS Header EAP PayloadUDP Header

802.11 Authentication Flow802.11 Authentication Flow

Basic 802.11 Security: SSID (the bottom Basic 802.11 Security: SSID (the bottom line)line)

SSID (Service Set Identifier) or ESSID (Extended SSID (Service Set Identifier) or ESSID (Extended Service Set Identifier)Service Set Identifier) Each AP has an SSID that it uses to identify itself. Each AP has an SSID that it uses to identify itself.

Network configuration requires each wireless client to Network configuration requires each wireless client to know the SSID of the AP to which it wants to connect. know the SSID of the AP to which it wants to connect.

SSID provides a very modest amount of control. It keeps SSID provides a very modest amount of control. It keeps a client from accidentally connecting to a neighboring AP a client from accidentally connecting to a neighboring AP only. It does not keep an attacker out. only. It does not keep an attacker out.

SSIDSSID SSID (Service Set Identifier) or ESSID SSID (Service Set Identifier) or ESSID

(Extended Service Set Identifier)(Extended Service Set Identifier) The SSID is a token that identifies an 802.11 The SSID is a token that identifies an 802.11

network. The SSID is a secret key that is set by network. The SSID is a secret key that is set by the network administrator. Clients must know the the network administrator. Clients must know the SSID to join an 802.11 network; however, network SSID to join an 802.11 network; however, network sniffing can discover the SSID.sniffing can discover the SSID.

The fact that the SSID is a secret key instead of a The fact that the SSID is a secret key instead of a public key creates a management problem for the public key creates a management problem for the network administrator.network administrator.

• Every user of the network must configure the SSID into Every user of the network must configure the SSID into their system. If the network administrator seeks to lock a their system. If the network administrator seeks to lock a user out of the network, the administrator must change user out of the network, the administrator must change the SSID of the network, which requires reconfiguration the SSID of the network, which requires reconfiguration of every network node. Some 802.11 NICs allow you to of every network node. Some 802.11 NICs allow you to configure several SSIDs at one time.configure several SSIDs at one time.

Basic 802.11 Security: MAC FiltersBasic 802.11 Security: MAC Filters

MAC filtersMAC filters Some APs provide the capability for checking the MAC Some APs provide the capability for checking the MAC

address of the client before allowing it to connect to the address of the client before allowing it to connect to the network. network.   

Using MAC filters is considered to be very weak security Using MAC filters is considered to be very weak security because with many Wi-Fi client implementations it is because with many Wi-Fi client implementations it is possible to change the MAC address by reconfiguring possible to change the MAC address by reconfiguring the card. the card.

An attacker could sniff a valid MAC address from the An attacker could sniff a valid MAC address from the wireless network traffic .wireless network traffic .

Basic 802.11 Security: WEPBasic 802.11 Security: WEP Static WEP keysStatic WEP keys

Wired Equivalent Privacy (WEP)Wired Equivalent Privacy (WEP) is part of the 802.11 is part of the 802.11 specification. specification.

Static WEP key operation requires keys on the client and AP Static WEP key operation requires keys on the client and AP that are used to encrypt data sent between them. With WEP that are used to encrypt data sent between them. With WEP encryption, sniffing is eliminated and session hijacking is encryption, sniffing is eliminated and session hijacking is difficult (or impossible). difficult (or impossible).

Client and AP are configured with a set of 4 keys, and when Client and AP are configured with a set of 4 keys, and when decrypting each are used in turn until decryption is decrypting each are used in turn until decryption is successful. This allows keys to be changed dynamically.successful. This allows keys to be changed dynamically.

Keys are the same in all clients and AP. This means that Keys are the same in all clients and AP. This means that there is a “community” key shared by everyone using the there is a “community” key shared by everyone using the same AP. The danger is that if any one in the community is same AP. The danger is that if any one in the community is compromised, the community key, and hence the network compromised, the community key, and hence the network and everyone else using it, is at risk.and everyone else using it, is at risk.

WEP – How?WEP – How? When WEP is active in a wireless LAN, each 802.11 packet is When WEP is active in a wireless LAN, each 802.11 packet is

encrypted separately with a RC4 cipher stream generated by encrypted separately with a RC4 cipher stream generated by a 64 bit RC4 key. This key is composed of a 24 bit a 64 bit RC4 key. This key is composed of a 24 bit initialization vector (IV) and a 40 bit WEP key.initialization vector (IV) and a 40 bit WEP key.

The encrypted packet is generated with a bit-wise exclusive The encrypted packet is generated with a bit-wise exclusive OR (XOR) of the original packet and the RC4 stream.OR (XOR) of the original packet and the RC4 stream.

The IV is chosen by the sender and should be changed so The IV is chosen by the sender and should be changed so that every packet won't be encrypted with the same cipher that every packet won't be encrypted with the same cipher stream. stream.

The IV is sent in the clear with each packet. The IV is sent in the clear with each packet. An additional 4 byte Integrity Check Value (ICV) is computed An additional 4 byte Integrity Check Value (ICV) is computed

on the original packet using the CRC-32 checksum algorithm on the original packet using the CRC-32 checksum algorithm and appended to the end. and appended to the end.

The ICV (be careful not to confuse this with the IV) is also The ICV (be careful not to confuse this with the IV) is also encrypted with the RC4 cipher stream. encrypted with the RC4 cipher stream.

WEP – Sending

Compute Integrity Check Vector (ICV). Provides integrity 32 bit Cyclic Redundancy Check. Appended to message to create plaintext.

Plaintext encrypted via RC4 Provides confidentiality. Plaintext XORed with long key stream of pseudorandom bits.

Key stream is function of 40-bit secret key 24 bit initialization vector (IV).

Ciphertext is transmitted.

WEP – Receiving

Ciphertext is received. Ciphertext decrypted via RC4

Ciphertext XORed with long key stream of pseudo random bits.

Key stream is function of• 40-bit secret key• 24 bit initialization vector (IV)

Check ICV Separate ICV from message. Compute ICV for message Compare with received ICV

WEP - WeaknessesWEP - Weaknesses Key Management and Key SizeKey Management and Key Size

Key management is not specified in the WEP standard, and Key management is not specified in the WEP standard, and therefore is one of its weaknesses, because without therefore is one of its weaknesses, because without interoperable key management, keys will tend to be long-interoperable key management, keys will tend to be long-lived and of poor quality.lived and of poor quality.

The Initialization Vector (IV) is Too SmallThe Initialization Vector (IV) is Too Small WEP’s IV size of 24 bits provides for 16,777,216 different WEP’s IV size of 24 bits provides for 16,777,216 different

RC4 cipher streams for a given WEP key, for any key size. RC4 cipher streams for a given WEP key, for any key size. Remember that the RC4 cipher stream is XOR-ed with the Remember that the RC4 cipher stream is XOR-ed with the original packet to give the encrypted packet which is original packet to give the encrypted packet which is transmitted, and the IV is sent in the clear with each packet.transmitted, and the IV is sent in the clear with each packet.

The Integrity Check Value (ICV) algorithm is not appropriateThe Integrity Check Value (ICV) algorithm is not appropriate The WEP ICV is based on CRC-32, an algorithm for The WEP ICV is based on CRC-32, an algorithm for

detecting noise and common errors in transmission. CRC-32 detecting noise and common errors in transmission. CRC-32 is an excellent checksum for detecting errors, but an awful is an excellent checksum for detecting errors, but an awful choice for a cryptographic hash.choice for a cryptographic hash.

WEP - WeaknessesWEP - Weaknesses WEP’s use of RC4 is weakWEP’s use of RC4 is weak

RC4 in its implementation in WEP has been found to have RC4 in its implementation in WEP has been found to have weak keys. Having a weak key means that there is more weak keys. Having a weak key means that there is more correlation between the key and the output than there should correlation between the key and the output than there should be for good security. Determining which packets were be for good security. Determining which packets were encrypted with weak keys is easy because the first three encrypted with weak keys is easy because the first three bytes of the key are taken from the IV that is sent bytes of the key are taken from the IV that is sent unencrypted in each packet. unencrypted in each packet.

This weakness can be exploited by a passive attack. All the This weakness can be exploited by a passive attack. All the attacker needs to do is be within a hundred feet or so of the attacker needs to do is be within a hundred feet or so of the AP.AP.

Authentication Messages can be easily forgedAuthentication Messages can be easily forged 802.11 defines two forms of authentication: 802.11 defines two forms of authentication:

• Open System (no authentication) and Open System (no authentication) and • Shared Key authentication. Shared Key authentication.

These are used to authenticate the client to the access These are used to authenticate the client to the access point. point.

• The idea was that authentication would be better than no The idea was that authentication would be better than no authentication because the user has to prove knowledge of the authentication because the user has to prove knowledge of the shared WEP key, in effect, authenticating himself. shared WEP key, in effect, authenticating himself.

Authentication TypeAuthentication Type

An access point must authenticate a station before the An access point must authenticate a station before the station can associate with the access point or station can associate with the access point or communicate with the network. The IEEE 802.11 communicate with the network. The IEEE 802.11

standard defines two types of authentication:standard defines two types of authentication: Open System AuthenticationOpen System Authentication Shared Key AuthenticationShared Key Authentication

Authentication Type: Open System Authentication Type: Open System AuthenticationAuthentication

The following steps occur when two devices use Open The following steps occur when two devices use Open System Authentication:System Authentication:

The station sends an authentication request to the access point.The station sends an authentication request to the access point. The access point authenticates the station.The access point authenticates the station. The station associates with the access point and joins the The station associates with the access point and joins the

network.network.

The process is illustrated below.The process is illustrated below.

Authentication Type: Shared Key Authentication Type: Shared Key

AuthenticationAuthentication The following steps occur when two devices use The following steps occur when two devices use

Shared Key Authentication:Shared Key Authentication:1.1. The station sends an authentication request to the access point.The station sends an authentication request to the access point.

2.2. The access point sends challenge text to the station.The access point sends challenge text to the station.

3.3. The station uses its configured 64-bit or 128-bit default key to The station uses its configured 64-bit or 128-bit default key to encrypt the challenge text, and sends the encrypted text to the encrypt the challenge text, and sends the encrypted text to the access point.access point.

4.4. The access point decrypts the encrypted text using its configured The access point decrypts the encrypted text using its configured WEP Key that corresponds to the stationWEP Key that corresponds to the station’’s default key.s default key.

5.5. The access point compares the decrypted text with the original The access point compares the decrypted text with the original challenge text. If the decrypted text matches the original challenge challenge text. If the decrypted text matches the original challenge text, then the access point and the station share the same WEP text, then the access point and the station share the same WEP Key and the access point authenticates the station. Key and the access point authenticates the station.

6.6. The station connects to the network.The station connects to the network.

Authentication Type: Shared Key Authentication Type: Shared Key AuthenticationAuthentication If the decrypted text does not match the original challenge text If the decrypted text does not match the original challenge text

(i.e., the access point and station do not share the same WEP (i.e., the access point and station do not share the same WEP Key), then the access point will refuse to authenticate the station Key), then the access point will refuse to authenticate the station and the station will be unable to communicate with either the and the station will be unable to communicate with either the 802.11 network or Ethernet network.802.11 network or Ethernet network.

The process is illustrated in below.The process is illustrated in below.

Configuring WEP ParametersConfiguring WEP Parameters Before enabling WEP on an 802.11 network, you must first Before enabling WEP on an 802.11 network, you must first

consider what type of encryption you require and the key size consider what type of encryption you require and the key size you want to use. Typically, there are three WEP Encryption you want to use. Typically, there are three WEP Encryption options available for 802.11 products:options available for 802.11 products:

Do Not Use WEP: Do Not Use WEP: The 802.11 network does not encrypt data. For The 802.11 network does not encrypt data. For authentication purposes, the network uses Open System authentication purposes, the network uses Open System Authentication.Authentication.

Use WEP for Encryption: Use WEP for Encryption: A transmitting 802.11 device encrypts A transmitting 802.11 device encrypts the data portion of every packet it sends using a configured WEP the data portion of every packet it sends using a configured WEP Key. The receiving device decrypts the data using the same WEP Key. The receiving device decrypts the data using the same WEP Key. For authentication purposes, the wireless network uses Open Key. For authentication purposes, the wireless network uses Open System Authentication.System Authentication.

Use WEP for Authentication and Encryption: Use WEP for Authentication and Encryption: A transmitting A transmitting 802.11 device encrypts the data portion of every packet it sends 802.11 device encrypts the data portion of every packet it sends using a configured WEP Key. The receiving 802.11 device decrypts using a configured WEP Key. The receiving 802.11 device decrypts the data using the same WEP Key. For authentication purposes, the the data using the same WEP Key. For authentication purposes, the 802.11 network uses Shared Key Authentication.802.11 network uses Shared Key Authentication.

Note: Note: Some 802.11 access points also support Some 802.11 access points also support Use WEP for Use WEP for Authentication Only Authentication Only (Shared Key Authentication without data (Shared Key Authentication without data encryption). encryption).

Recommended 802.11 Security PracticesRecommended 802.11 Security Practices Change the default password for the Admin accountChange the default password for the Admin account SSIDSSID

• Change the defaultChange the default• Disable Broadcast Disable Broadcast • Make it unique Make it unique • If possible, Change it oftenIf possible, Change it often

Enable MAC Address FilteringEnable MAC Address Filtering Enable WEP 128-bit Data Encryption. Please note that Enable WEP 128-bit Data Encryption. Please note that

this will reduce your network performancethis will reduce your network performance• Use the highest level of encryption possible Use the highest level of encryption possible • Use a “Shared” Key Use a “Shared” Key • Use multiple WEP keys Use multiple WEP keys • Change it regularlyChange it regularly

Turn off DHCPTurn off DHCP Refrain from using the default IP subnetRefrain from using the default IP subnet

VulnerabilitiesVulnerabilities

VulnerabilitiesVulnerabilities

There are several known types of wireless attacks There are several known types of wireless attacks that must be protected against:that must be protected against: SSID (network name) sniffingSSID (network name) sniffing WEP encryption key recovery attacksWEP encryption key recovery attacks ARP poisoning (“man in the middle attacks”)ARP poisoning (“man in the middle attacks”) MAC address spoofingMAC address spoofing Access Point management password and SNMP attacksAccess Point management password and SNMP attacks Wireless end user (station) attacksWireless end user (station) attacks Rogue AP attacks (AP impersonation)Rogue AP attacks (AP impersonation) DOS (denial of service) wireless attacksDOS (denial of service) wireless attacks

802.1x802.1x

IEEE802.1x is the denotation of a standard that is IEEE802.1x is the denotation of a standard that is titled “Port Based Network Access Control”, which titled “Port Based Network Access Control”, which indicates that the emphasis of the standard is to indicates that the emphasis of the standard is to provide a control mechanism to connect physically to provide a control mechanism to connect physically to a LAN. a LAN.

The standard does not define the authentication The standard does not define the authentication methods, but it does provide a framework that allows methods, but it does provide a framework that allows the application of this standard in combination with the application of this standard in combination with any chosen authentication method. any chosen authentication method.

It adds to the flexibility as current and future It adds to the flexibility as current and future authentication methods can be used without having authentication methods can be used without having to adapt the standard.to adapt the standard.

802.1x Components802.1x Components

The 802.1x standard recognizes the following The 802.1x standard recognizes the following concepts:concepts:   Port Access Entity (PAE)Port Access Entity (PAE)

• which refers to the mechanism (algorithms and protocols) which refers to the mechanism (algorithms and protocols) associated with a LAN port (residing in either a Bridge or a associated with a LAN port (residing in either a Bridge or a Station)Station)

  Supplicant PAESupplicant PAE• which refers to the entity that requires authentication before which refers to the entity that requires authentication before

getting access to the LAN (typically in the client station)getting access to the LAN (typically in the client station) Authenticator PAEAuthenticator PAE

• which refers to the entity facilitating authentication of a which refers to the entity facilitating authentication of a supplicant (typically in bridge or AP) supplicant (typically in bridge or AP)

Authentication serverAuthentication server• which refers to the entity that provides authentication service to which refers to the entity that provides authentication service to

the Authenticators in the LAN (could be a RADIUS server)the Authenticators in the LAN (could be a RADIUS server)

General Description ofGeneral Description ofIEEE 802.1x TerminologyIEEE 802.1x Terminology

Supplicant Authentication ServerAuthenticator

Operates on client Processes EAP requestsOperates on devices at network edge, like

APs and switches

wireless networkwireless network enterprise networkenterprise networkenterprise edgeenterprise edge

EAP over wirelessEAP over wireless EAP over RADIUSEAP over RADIUSRADIUS server

EAP – MD5EAP – MD5

WPAWPA Wi-Fi Protected Access (WPA)Wi-Fi Protected Access (WPA) is a new security guideline is a new security guideline

issued by the Wi-Fi Alliance. issued by the Wi-Fi Alliance. The goal is to strengthen security over the current WEP The goal is to strengthen security over the current WEP

standards by including mechanisms from the emerging standards by including mechanisms from the emerging 802.11i standard for both data encryption and network 802.11i standard for both data encryption and network

access control.access control. Path: WEP -> WPA -> 802.11iPath: WEP -> WPA -> 802.11i WPA = TKIP(WPA = TKIP(Temporal Key Integrity ProtocolTemporal Key Integrity Protocol)) + IEEE + IEEE

802.1x802.1x For encryption, WPA has TKIP, which uses the same For encryption, WPA has TKIP, which uses the same

encryption algorithm as WEP, but constructs keys in a encryption algorithm as WEP, but constructs keys in a different way. different way.

For access control, WPA will use the IEEE 802.1x For access control, WPA will use the IEEE 802.1x protocol. protocol.

802.11i – Future Wireless Security 802.11i – Future Wireless Security StandardStandard

Task group "i" within the IEEE 802.11 is responsible for Task group "i" within the IEEE 802.11 is responsible for developing a new standard for WLAN security to replace developing a new standard for WLAN security to replace the weak WEP (Wired Equivalent Privacy). the weak WEP (Wired Equivalent Privacy).

The IEEE 802.11i standard utilizes the authentication The IEEE 802.11i standard utilizes the authentication schemes of 802.1x and EAP(Extensible Authentication schemes of 802.1x and EAP(Extensible Authentication Protocol) in addition to a new encryption scheme Protocol) in addition to a new encryption scheme –– AES AES (Advanced Encryption Standard) and dynamic key (Advanced Encryption Standard) and dynamic key distribution scheme - TKIP(Temporal Key Integrity distribution scheme - TKIP(Temporal Key Integrity Protocol).Protocol).

802.11i = 802.11i = TKIP + IEEE 802.1xTKIP + IEEE 802.1x + AES + AES