© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0— © 2003, Cisco Systems, Inc. All rights reserved.

FWL 1.0—8-2 Module 8 Security

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-3 Overview WLANs present unique security challenges. This module will cover the basics of securing WLANs. Specific weaknesses and vulnerabilities of WLANs will be covered. Security configuration for APs, bridges, and clients will be shown and explained. Finally, enterprise level WLAN security will be presented.

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-4 Learning Objectives Understand the 3 types of vulnerabilities and attacks Understand the 4 types of threats Understand the importance of a security policy Understand the 4 steps of the WLAN security wheel Properly configure basic WLAN security via IOS GUI and CLI Understand advance enterprise level WLAN security technologies and configuration principles

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-5 Advanced Security Terms WEP – Wired Equivalent Privacy EAP – Extensible Authentication Protocol TKIP – Temporal Key Integrity Protocol CKIP – Cisco Key Integrity Protocol CMIC – Cisco Message Integrity Check Broadcast Key Rotation – Group Key Update WPA – Wi-Fi Protected Access (WPA)

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-6 Balancing Security and Access

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-7 Vulnerabilities Technology –TCP/IP –WEP and Broadcast SSID –Association Process –Wireless Interference Configuration –Default passwords –Unneeded Services enabled –Few or no filters –Poor device maintenance Policy –Weak Security Policy –No Security Policy –Poorly enforced Policy –Physical Access –Poor or no monitoring

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-8 Threats Internal External Structured Unstructured

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-9 The Security Attack—Recon and Access

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-10 The Security Attacks—DoS

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-11 WLAN Security Wheel Always have a good WLAN Security Policy in place. Secure the network based on the policy

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-12 WLAN Security Considerations Authentication – only authorized users and devices should be allowed. Encryption – traffic should be protected from unauthorized access. Administration Security – only authorized users should be able to access and configure the AP configuration interfaces.

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-13 Common Protocols which use Encryption When using a public network such as a WLAN, FTP, HTTP, POP3, and SMTP are insecure and should be avoided whenever possible. Utilize protocols with encryption. Traffic No Encryption Encryption Web Browsing HTTPS * HTTP File Transfer TFTP or FTP SCP Remote Mgmt POP3 or SMTP SPOP3 * Telnet SSH * SSL/TLS

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-14 WLAN Security Hierarchy Virtual Private Network (VPN) No Encryption, Basic Authentication Public “Hotspots” Open Access 40-bit or 128-bit Static WEP Encryption Home Use Basic Security 802.1x, TKIP/WPA Encryption, Mutual Authentication, Scalable Key Mgmt., etc. Business Enhanced Security Remote Access Business Traveler, Telecommuter

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-15 Basic WLAN Security

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-16 Admin Authentication on AP To prevent unauthorized access to the AP configuration interfaces: Configure a secret password for the privileged mode access. (good) Configure local usernames/passwords. (better) Configure AP to utilize a security server for user access. (best)

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-17 Console Password

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-18 WEP WEP is a key. WEP scrambles communications between AP and client. AP and client must use same WEP keys. WEP keys encrypt unicast and multicast. WEP is easily attacked

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-19 Supported Devices What can be a client? Client Non-Root bridge Repeater access point Workgroup Bridge Authenticator? Root access point Root bridge ?

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-20 Authentication Types Open Authentication to the Access Point Shared Key Authentication to the Access Point EAP Authentication to the Network MAC Address Authentication to the Network Combining MAC-Based, EAP, and Open Authentication Using CCKM for Authenticated Clients Using WPA Key Management

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-21 WLAN Security: 802.1X Authentication Mutual Authentication EAP-TLS EAP-Transport Layer Security Mutual Authentication implementation Used in WPA interoperability testing LEAP “Lightweight” EAP Nearly all major OS’s supported: –WinXP/2K/NT/ME/98/95/CE, Linux, Mac, DOS PEAP “Protected” EAP Uses certificates or One Time Passwords (OTP) Supported by Cisco, Microsoft, & RSA GTC (Cisco) & MSCHAPv2 (Microsoft) versions Client AP Radius Server

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-22 EAP Extensible Authentication Protocol (802.1x authentication) Provides dynamic WEP keys to user devices. Dynamic is more secure, since it changes. Harder for intruders to hack…by the time they have performed the calculation to learn the key, they key has changed!

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-23 Basic RADIUS Topology RADIUS can be implemented: Locally on an IOS AP Up to 50 users On a ACS Server

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-24 Enterprise Encryption

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-25 WPA Interoperable, Enterprise-Class Security

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-26 Cipher “Suite” Cipher suites are sets of encryption and integrity algorithms. Suites provide protection of WEP and allow use of authenticated key management. Suites with TKIP provide best security. Must use a cipher suite to enable: WPA – Wi-Fi Protected Access CCKM – Cisco Centralized Key Management

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-27 Configuring the Suite Create WEP keys Enable Cipher “Suite” and WEP Configure Broadcast Key Rotation Follow the Rules

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-28 WEP Key Restrictions Security ConfigurationWEP Restriction CCKM or WPA key mgt.No WEP in slot 1 LEAP or EAPNo WEP in slot 4 40-bit WEPNo 128-bit key 128-bit WEPNo 40-bit key TKIPNo WEP keys TKIP and 40 or 128 WEPNo WEP in slot 1 and 4 Static WEP w/MIC or CMIC WEP and slots must match on AP & client Broadcast key rotationKeys in slots 2 & 3 overwritten

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-29 Security Levels

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-30 Enterprise WLAN Security Evolution TKIP/WPA Successor to WEP Cisco’s pre-standard TKIP has been shipping since Dec.’01 Cisco introduced TKIP into i committee i-standardized TKIP part of Wi-Fi Protected Access (WPA) WPA software upgrade now available for AP1100 & AP1200 AES The “Gold Standard” of encryption AES is part of i standard –- AES will be part of WPA2 standard (expected in 2004)

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-31 VLANs

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-32 VLANs Configuring your access point to support VLANs is a three-step process: Assign SSIDs to VLANs. Assign authentication settings to SSIDs. Enable the VLAN on the radio and Ethernet ports.

© 2003, Cisco Systems, Inc. All rights reserved. FWL 1.0—8-33 Using VLANs for Security SSID: data Security: PEAP + AES 802.1Q wired network w/ VLANs SSID: visitor Security: None AP Channel: 6  SSID “data” = VLAN 1  SSID “voice” = VLAN 2  SSID “visitor” = VLAN 3 SSID: voice Security: LEAP + WPA