1. 12-July-2006IETF 66, Montreal1 Implementation Experience with a New Wireless EAP Method David Mitton RSA Security, Inc.

2. 12-July-2006IETF 66, Montreal2 New EAP Method 32, SecurID Token Authentication Uses Protected-OTP EAP Framework draft-nystrom-eap-potp-04.txt EAP Method 32 - profile of POTP for RSA SecurID Applications: –Dial PPP –VPN (PPTP) –Wired 802.1x –802.11i Wireless 802.1x

3. 12-July-2006IETF 66, Montreal3 Problems with Wireless Deployment Development and testing on single vendor access point worked flawlessly When deployed to the field, began getting problem reports Three different vendors; three different types of problems

4. 12-July-2006IETF 66, Montreal4 Typical Components Diagram

5. 12-July-2006IETF 66, Montreal5 Typical Message Flow

6. 12-July-2006IETF 66, Montreal6 Case 1: Response Not Accepted EAP 32 Request message is forwarded from AP to STA, but AP returns EAP Failure upon receiving response. AP decides to block EAP based on method value.

7. 12-July-2006IETF 66, Montreal7 Case 2: Fumbled Forwarding EAP32 Request passes from RADIUS to EAPOL but not the Response Method dependencies in the code that packs and unpacks EAP messages from RADIUS messages Causes the AP to retransmit Request every 30 seconds. STA responds each time, but Response is lost Session-Timeout value (120) ignored by AP

8. 12-July-2006IETF 66, Montreal8 Case 3: Session Interference Re-sync condition causes a long authentication, AP decides to send new Identity Request to STA in midst of exchange. (2.5 seconds after previous exchange) AP has bad policy on length of authentication process. Not tied to message exchange. Did not honor Session-Timeout attribute in Access-Challenge.

9. 12-July-2006IETF 66, Montreal9 Bad Assumptions Method type #s should all be passed, or be management configurable Avoid method dependent processing for EAP forwarding – why? Session timeout should: –use Session-Timeout attribute, –sensitive to message ID change, and message to message timing, not overall elapsed time

10. 12-July-2006IETF 66, Montreal10 Suggested Testing Requirements Allow all method values Retransmission of individual messages should be manageable (Session-Timeout) Timeout of authentication session should be tied to session inactivity not arbitrary or inaccessible numbers Anything that returns keys should work (e.g. meets RFC 3748)

11. 12-July-2006IETF 66, Montreal11 How do we get Open and Interoperable EAP products? Products that only support a short list of protocols are preventing new security! Who is responsible? –Vendors? –Wi-Fi Alliance? –IEEE 802.11? What can we do here?