802.1X Authentication

1. 802.1X Authentication Deniz Kaya Microsoft, Cisco, Ironport Trainer CCSI, CCNP, MCT, MCSE, ICSI, ICSP

2. Airport …While the Assets Needing to be Protected are Expanding 831 Cable Provider Teleworker VPN Head-End Service Provider/ Internet Partner/Vendor City Hall Library One physical network, must accommodate multiple logical networks (user groups) each with own rules.

3. IDENTITY:So, you said MAC Address ? Win 2K & XP allow easy change for MAC addressesMAC address is not an authentication mechanism…

4. Determining “who” gets access and “what” they can do Campus Network User Based Policies Applied (BW, QoS etc) User Identity Based Network Access Unauthorized Users/Devices Authorized Users/Devices • Equivalent to placing a Security Guard at each Switch Port • Only Authorized users can get Network Access • Unauthorized users can be placed into “Guest” VLANs • Prevents unauthorized APs

5. What Exactly Is 802.1x? Standard set by the IEEE 802.1 working group. Describes a standard link layer protocol used for transporting higher-level authentication protocols. Works between the Supplicant and the Authenticator. Maintains backend communication to an Authentication Server.

6. Some IEEE Terminology

7. What Does it Do? Transport authentication information in the form of Extensible Authentication Protocol (EAP) payloads. The authenticator (switch) becomes the middleman for relaying EAP received in 802.1x packets to an authentication server by using RADIUS to carry the EAP information. 802.1x Header EAP Payload

8. What is RADIUS? RADIUS – The Remote Authentication Dial In User Service A protocol used to communicate between a network device and an authentication server or database. Allows the communication of login and authentication information. i.e.. Username/Password, OTP, etc. Allows the communication of arbitrary value pairs using “Vendor Specific Attributes” (VSAs). UDP Header RADIUS Header EAP Payload

9. 802.1x – enhancing LAN securityTopology

10. Wired Access Control Model Client and Switch Talk 802.1x Switch Speaks to Auth Server Using RADIUS Actual Authentication Conversation Is between Client and Auth Server Using EAP; the Switch Is Just a Middleman, but Is Aware of What’s Going on • RADIUS acts as the transport for EAP, from the authenticator (switch) to the authentication server (RADIUS server) • RADIUS is also used to carry policy instructions back to the authenticator in the form of AV pairs.

11. Identity Based Network Services Switch applies policies and enables port. 4000 Series 3550/2950 Series Login Request Login Info 6500 Series Access Points Login Good! Apply Policies Verify Login and Check with Policy DB Login + Certificate Login Verified • Set port to enable • set port vlan 10 802.1x Capable Client IEEE802.1x + VLANS + VVID + ACL + QoS VLAN 10 Engineering VLAN Active Directory Login and Certificate Services AAA Radius Server 802.1x Authentication Server 802.1x Capable Access Devices

12. 802.1x client implementation in Windows Wired interfaces – enabled by default Wireless interfaces – integrated with the wireless configuration client Enabled by default if privacy is enabled Dynamic keys usage enforcement User and computer authentication enabled by default

13. 802.1x in Microsoft WindowsMachine and user authentication Startup Machine Machine credentials available (use machine credentials) Machine authentication success Machine authentication failure User logon User credentials available (use user credentials) User authentication success User authentication failure User logoff

14. Windows Machine Authentication Power Up Load NDIS drivers 802.1x Authenticate as Computer Setup Secure Channel to DC Apply Computer GPOs Present GINA (Ctrl-Alt-Del) Login DHCP Update GPOs • What is Machine Authentication? • The ability of a Windows workstation to authenticate under it’s own identity, independent of the requirement for an interactive user session. • What is it used for? • Machine authentication is used at boot time by Windows OSes to authenticate and communicate with Windows Domain Controllers in order to pull down machine group policies. • Why do we care? • Pre-802.1x this worked under the assumption that network connectivity was a given. Post-802.1x the blocking of network access prior to 802.1x authentication breaks the machine based group policy model – UNLESS the machine can authenticate using its own identity in 802.1x .

15. 802.1x in Microsoft Windows802.1x authentication configuration page Same for wired and wireless Provides control over computer and guest authentication EAP method setting

16. What is EAP? EAP – The Extensible Authentication Protocol A flexible protocol used to carry arbitrary authentication information.

17. EAP method layer TLS MD5 PEAP MS-CHAPv2 TLS IKE GSS_API Kerberos EAP EAP layer PPP 802.3 802.5 802.11 Other… media layer

18. 802.1x authentication clientEAP methods available in Windows EAP-TLS (Transport Level Security) – default setting for 802.1x client in Windows PEAP (Protected EAP) allows inner methods TLS (certificate based) Microsoft Challenge Handshake Authentication Protocol v2 (MSCHAPv2) (password based) EAP-MD5 – available for wired networks only Doesn’t provide encrypted session between supplicant and authenticator Transfers password hashes in clear

19. 802.1x authentication clientEAP methods – wired and wireless networks

20. EAP with MD5 identity-request identity-response (username) MD5-challenge-request R = MD5(password,challenge) MD5-challenge-response Check that MD5(password,challenge) equals the response success or failure Peer Authenticator cleartext password cleartext password Random challenge

21. 802.1x with EAP-TLSLocal store certificates Uses both user and computer certificates Certificates deployed through auto-enrollment, Web enrollment, certificate import, or manual request using the Certificates snap-in Local computer store is always available The user store (for a current user) is only available after a successful user logon

22. 802.1x with EAP-TLSConfiguration page • Mutual authentication enabled by default • Simple certificate selection

23. 802.1x with EAP-TLSSmart card certificates User must enter PIN to access the certificate on the smart card. PIN input is not required again on subsequent re-authentication tries – like session time-out or roaming on wireless networks. When roaming out of range and back in range, user will be re-prompted for PIN. Managing user certificates stored on local hard drives can be difficult, and some users may move among computers.

24. 802.1x with PEAP-MSCHAPv2What to consider Password-based authentication – not all networks have a PKI deployment. Single sign-on (SSO). Enables both machine and user authentication. Windows logon credentials can be automatically used (default setting), or credentials can be provided by user.

25. 802.1x with PEAP-MSCHAPv2Configuration page By default, fast reconnect feature is disabled.

26. Campus Identity - Supplicants • Possible End-Points : • Windows XP – Yes • Windows 2000 – Yes (SP3 + KB) • Linux – Yes • HP-UX – Yes • Solaris - Yes • HP Printers – Yes • Windows 98 – Limited • Windows NT4 – Limited • Apple – yes • IP Phones – yes • WLAN APs – yes • …. HP Jet Direct Windows Solaris 7920 Apple WLAN APs IP Phones Pocket PC

27. 802.1xPort based network access control Falls under 802.1 NOT 802.11 This is a NETWORK standard, not a wireless standard Is PART of the 802.11i draft Provides Network Authentication, NOT encryption

28. Know before you start ! 802.1x Implementation requires various knowledge from different domains Switch or AP Compliance and configuration Certificate Services (Hidden part of the ICEBERG) if you intend to you EAP-TLS Radius Server, especially when you have a multi-domain-directory infrastructure Smart-card services, if you intend to use them instead of user certificates Various Client Deployment Scenarios

29. Demo – Wired Client Authentication 802.1x with PEAP-MSCHAPv2 Cisco Switch Configuration Active Directory Configuration Installation of IAS (Radius) Installation of Certificate Services XP Client Configuration

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