How Secure is Authentication?

Transcription

1 FIDO UAF Tutorial

2 How Secure is Authentication?

3 How Secure is Authentication?

4 How Secure is Authentication?

5 Cloud Authentication

6 Password Issues Password might be entered into untrusted App / Web-site ( phishing ) Password could be stolen from the server Inconvenient to type password on phone Too many passwords to remember re-use / cart abandonment

7 OTP Issues OTP vulnerable to realtime MITM and MITB attacks Inconvenient to type OTP on phone OTP HW tokens are expensive and people don t want another device SMS security questionable, especially when Device is the phone

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9 Summary 1. Passwords are insecure and inconvenient especially on mobile devices 2. Alternative authentication methods are silos and hence don t scale to large scale user populations 3. The required security level of the authentication depends on the use 4. Risk engines need information about the explicit authentication security for good decision

10 How does FIDO work? Device

11 How does FIDO work? challenge Require user gesture before private key can be used Private key (signed) response Public key

12 How does FIDO UAF work? SE

13 How does FIDO UAF work? Same User as enrolled before? Same Authenticator as registered before? Can recognize the user (i.e. user verification), but doesn t know its identity attributes.

14 How does FIDO UAF work? Same User as enrolled before? Same Authenticator as registered before? Identity binding to be done outside FIDO: This this John Doe with customer ID X. Can recognize the user (i.e. user verification), but doesn t know its identity attributes.

15 How does FIDO UAF work? How is the key protected (TPM, SE, TEE, )? Which user verification method is used? SE

16 Attestation & Metadata Signed Attestation Object Verify using trust anchor included in Metadata Private attestation key Understand Authenticator security characteristic by looking into Metadata from mds.fidoalliance.org (or other sources) Metadata

17 Binding Keys to Apps Use google.com key Use paypal.com key Use same user gesture (e.g. same finger or PIN) for unlocking each private key.

18 FIDO Building Blocks FIDO USER DEVICE BROWSER / APP FIDO CLIENT TLS Server Key UAF Protocol Cryptographic authentication key DB RELYING PARTY WEB APPLICATION FIDO SERVER ASM FIDO AUTHENTICATOR Authentication keys Attestation key Authenticator Metadata Update METADATA SERVICE

19 Registration Overview Perform legacy authentication first, in order to bind authenticator to an electronic identity, then perform FIDO registration. Send Registration Request: - Policy - Random Challenge FIDO CLIENT FIDO SERVER FIDO AUTHENTICATOR Start registration Verify user Generate key pair Sign attestation object: Public key AAID Random Challenge Name of relying party Signed by attestation key Verify signature Check AAID against policy Store public key AAID = Authenticator Attestation ID, i.e. model ID

20 UAF Authentication FIDO Authenticator App 0 Prepare Web App FIDO Server

21 UAF Authentication FIDO Authenticator App 0 Prepare Web App FIDO Server

22 UAF Authentication FIDO Authenticator App 0 Prepare Web App FIDO Server

23 UAF Authentication FIDO Authenticator App 0 1 Prepare Initiate Authentication Web App FIDO Server

24 UAF Authentication FIDO Authenticator App 0 1 Prepare Initiate Authentication Auth. Request with Challenge Web App FIDO Server 2

25 UAF Authentication Pat Johnson FIDO Authenticator App 0 1 Prepare Initiate Authentication Auth. Request with Challenge Web App FIDO Server 2 3 Verify User & Sign Challenge (Key specific to RP Webapp)

26 UAF Authentication Pat Johnson 650 Castro Street Mountain View, CA United States FIDO Authenticator App Prepare Initiate Authentication Auth. Request with Challenge Auth. Response Web App FIDO Server 2 3 Verify User & Sign Challenge (Key specific to RP Webapp)

27 UAF Authentication Pat Johnson Payment complete! Return to the merchant s web site to continue shopping Return to the merchant FIDO Authenticator App Prepare Initiate Authentication Auth. Request with Challenge Auth. Response Success Web App FIDO Server Verify User & Sign Challenge (Key specific to RP Webapp)

28 Transaction Confirmation Device Relying Party FIDO Authenticator Browser or Native App 1 Initiate Transaction Web App FIDO Server Authentication Request + Transaction Text Display Text, Verify User & Unlock Private Key (specific to User + RP Webapp) Authentication Response + Text Hash, signed by User s private key 5 Validate Response & Text Hash using User s Public Key

29 Convenience & Security Security Password Convenience

30 Convenience & Security Security Password + OTP Password Convenience

31 Convenience & Security Security In FIDO: Same user verification method for all servers FIDO Password + OTP Password In FIDO: Arbitrary user verification methods are supported (+ they are interoperable) Convenience

32 Convenience & Security Security In FIDO: Scalable security depending on Authenticator implementation FIDO Password + OTP Password In FIDO: Only public keys on server Not phishable Convenience

33 FIDO Authenticator Concept Optional Components Injected at manufacturing, doesn t change FIDO Authenticator User Verification / Presence Transaction Confirmation Display Attestation Key Authentication Key(s) Generated at runtime (on Registration)

34 What about rubber fingers? Protection methods in FIDO 1. Attacker needs access to the Authenticator and swipe rubber finger on it. This makes it a non-scalable attack. 2. Authenticators might implement presentation attack detection methods. Remember: Creating hundreds of millions of rubber fingers + stealing the related authenticators is expensive. Stealing hundreds of millions of passwords from a server has low cost per password.

35 But I can t revoke my finger Protection methods in FIDO You don t need to revoke your finger, you can simply de-register the old (=attacked) authenticator. Then, 1. Get a new authenticator 2. Enroll your finger (or iris, ) to it 3. Register the new authenticator to the service

36 FIDO & Federation First Mile Second Mile FIDO USER DEVICE IdP Service Provider BROWSER / APP FIDO Protocol FEDERATION SERVER Federation FIDO CLIENT Id DB FIDO AUTHENTICATOR FIDO SERVER Knows details about the Authentication strength Knows details about the Identity and its verification strength.

37 FIDO & Federation in Enterprise Cloud-hosted Appl. 1 Cloud-hosted Appl. 2 Federated Login, e.g. OpenID Connect Cloud-hosted Appl. N Enterprise IT Enterprise Appl. 1 Enterprise Appl. 2 Internal User Enterprise Appl. N IdP FEDERATION SERVER External User Could be operated externally as well FIDO SERVER

38 FIDO UAF Enabled Products Samsung Sony Sharp Galaxy S6, S6 Edge, S6 Edge+ Galaxy Tab S Galaxy Note 5 Galaxy S5, S5 Mini, S5 Plus Galaxy Alpha Galaxy Note 4, Note 4 Edge Galaxy Tab S Xperia Z5, Z5 Compact, Z5 Premium OEM Enabled Smartphones & Tablets Aquos Zeta SH-03G, SH01H Fujitsu Arrows NX F-04G, Fit F-01H, NX F-02H Clients available for these operating systems: Software Authenticator Examples: Speaker/Face recognition, PIN, QR Code, etc. Aftermarket Hardware Authenticator Examples: USB fingerprint scanner, MicroSD Secure Element

39 FIDO is used Today

40 Typical RP Deployment FIDO USER DEVICE MOBILE APP Challenge: Old devices do not have a native FIDO Stack FIDO CLIENT ASM FIDO AUTHENTICATOR Native FIDO Stack (not on old devices)

41 Typical RP Deployment FIDO USER DEVICE MOBILE APP App SDK FIDO CLIENT ASM AUTHENR Challenge: Old devices do not have a native FIDO Stack Solution: embed FIDO Stack in App SDK Embedded FIDO Stack FIDO CLIENT ASM FIDO AUTHENTICATOR Native FIDO Stack (not on old devices)

42 Typical Native FIDO Stack FIDO USER DEVICE (SMARTPHONE) Fingerprint is mostly used today. Typically on high-end devices. Some devices use eye/iris as modality. No need for expensive FP Sensors. FIDO CLIENT ASM FIDO AUTHENTICATOR Rich Execution Environment, e.g. Android. Trusted Execution Environment (TEE)

43 Rolf Lindemann, Nok Nok Labs, Conclusion Different authentication use-cases lead to different authentication requirements FIDO separates user verification from authentication and hence supports all user verification methods FIDO supports scalable convenience & security User verification data is known to Authenticator only FIDO complements federation

44 How does FIDO UAF work? 6. Use site-specific keys in order to protect privacy 4. Provide cryptographic proof of authenticator model 3. Store public keys on the server (no secrets) 2. Define policy of acceptable Authenticators 8. Use channel binding to protect against MITM 7. Verify user before signing authentication response 5. Generate key pair in Authenticator to protect against phishing 1. Use Metadata to understand Authenticator security characteristic

45 Physical attacks possible on lost or stolen devices ( 3% in the US in 2013) Classifying Threats 5 Physically attacking user devices steal data for impersonation 6 Physically attacking user devices misuse them for impersonation Scalable attacks Remotely attacking lots of user devices Remotely attacking lots of user devices steal data for impersonation misuse them for impersonation Remotely attacking lots of user devices misuse authenticated sessions 1 Remotely attacking central servers steal data for impersonation

46 Registration Overview (2) Relying Party foo.com Physical Identity Know Your Customer rules WEB Application Legacy Authentication { userid=1234, jane@mail.com, known since 03/05/04, payment history=xx, } Virtual Identity FIDO AUTHENTICATOR AAID y key for foo.com: 0xfa4731 Link new Authenticator to existing userid Registration FIDO SERVER { userid=1234, pubkey=0x43246, AAID=x +pubkey=0xfa4731, AAID=y }

47 Using Secure Hardware PIN Entry User Verification / Presence SIM Card FIDO Authenticator Attestation Key PIN Verification Authentication Key(s)

48 Client Side Biometrics Trusted Execution Environment (TEE) FIDO Authenticator as Trusted Application (TA) User Verification / Presence Attestation Key Store at Enrollment Authentication Key(s) Compare at Authentication Unlock after comparison

49 Combining TEE and SE Trusted Execution Environment (TEE) Secure Element FIDO Authenticator as Trusted Application (TA) e.g. GlobalPlatform Trusted UI User Verification / Presence Transaction Confirmation Display Attestation Key Authentication Key(s)