Lecture 11 Wireless security

Wireless Networks Standard Wireless networks are standardized by IEEE. Under 802 LAN MAN standards committee. Application Presentation Session IEEE 802 standards Transport Same organization that came up with IEEE 802.3 Ethernet, which is responsible for success of Internet Network Logical Link Control Data Link Medium Access (MAC) Physical Physical (PHY) ISO - OSI

DSSS Direct Sequence Signaling (DSSS) Using one of 11 overlapping 22MHz channels, multiply the data by an 11-bit number to spread the 1M-symbol/sec data over 11MHz. It use the 2.4 GHz band Requires RF linearity over 11MHz Spreading yields processing gain at receiver Less immune to interference

IEEE 802.11g Introduced in 2003 Combine the feature of both standards (a,b) 100-150 feet range 54 Mbps Speed 2.4 GHz radio frequencies Compatible with ‘b’

Comparison 3G versus WiFi Standard WCDMA,CDMA2000 IEEE 802.11 Max Speed 2 Mbps 54 Mbps Operations Cell phone companies Individuals, WISP License Yes No Coverage Area Several km About 100m Advantages Range, mobility Speed, cheap Disadvantages Relatively slow Expensive Short range

Comparison 3G versus WiMax Wi-Max (Wider-Fi) Standard WCDMA,CDMA2000 IEEE 802.16 Max Speed 2 Mbps 10 to 100 Mbps Operations Cell phone companies Individuals, WISP License Yes Yes/No Coverage Area Several km Advantages Range, mobility Speed, long range Disadvantages Relatively slow Expensive Interference issues?

MITM Attack Attacker spoofes a disassociate message from the victim The victim starts to look for a new access point, and the attacker advertises his own AP on a different channel, using the real AP’s MAC address The attacker connects to the real AP using victim’s MAC address

WEP vs WPA vs WPA2 WEP WPA WPA2 Cript RC4 AES Key rotation None Dynamic session keys Key distribution Manual inert over each device Automatic distribution is possible Authentification Use WEP key 802.1x & EAP supported

Authentification (802.1x / EAP) EAP - Extensible Authentication Protocol 802.1X parte din 802.11i Must certify the user not only the devices Mutual authentification 802.1x authentification Key management EAP Model Addition to the Wi-Fi Protected Access. Used in internal network. Extra security for enterprise and government Wi-Fi LANs. Several versions available.

802.1x

802.1x Access Control Designed as a general purpose network access control mechanism Not Wi-Fi specific Authenticate each client connected to AP (for WLAN) or switch port (for Ethernet) Authentication is done with the RADIUS server, which ”tells” the access point whether access to controlled ports should be allowed or not AP forces the user into an unauthorized state user send an EAP start message AP return an EAP message requesting the user’s identity Identity send by user is then forwared to the authentication server by AP Authentication server authenticate user and return an accept or reject message back to the AP If accept message is return, the AP changes the client’s state to authorized and normal traffic flows

WLAN security methods comparision Security type Security level Install & maintenance Integration & easiest to use WEP Static Low High IEEE 802.1X PEAP Midle IEEE 802.1x TLS

References Mustafa Ergen, IEEE 802.11 Overview, http://wow.eecs.berkeley.edu/ergen/docs/IEEE-802.11overview.ppt Greg Goldman, Is for “Wireless Fidelity” or IEEE 802.11 Standard, http://www.khirman.com/files/image/ppt/WiFi.ppt tcil-india.com/new/new.../TCIL%2010%20WiFi %20Technology.ppt

No wireless is 100% secure!