Touch ID and Face ID. Is It Secure?

Transcript

1. OWASP ZHYTOMYR. 29 JUNE 2019. JULIA POTAPENKO TOUCH ID AND

   FACE ID IS IT SECURE?

2. OWASP ZHYTOMYR. 29 JUNE 2019. JULIA POTAPENKO TOUCH ID AND

   FACE ID IS IT SECURE? Cats Edition

3. JULIA POTAPENKO • iOS Software Engineer at Stuzo • Mobile

   Dev Lead at WWCode Kyiv • Co-organizer of OWASP Zhytomyr • Speaker at OWASP, CocoaHeads, WWCode and WTM events

4. WE WILL TALK ABOUT ★ Touch ID and Face ID

   ★ Secure Enclave ★ Keychain

5. WE WILL TALK ABOUT ★ Touch ID and Face ID

   ★ Secure Enclave ★ Keychain How to do it? What can go wrong?

6. TOUCH ID AND FACE ID LOCAL AUTHENTICATION

7. TOUCH ID AND FACE ID LOCAL AUTHENTICATION USER PROTECTED RESOURCES

   PROTECTED ACTIONS

8. LOCAL AUTHENTICATION https://support.apple.com/en-us/HT204587 https://developer.apple.com/documentation/localauthentication

9. SECURE ENCLAVE CREATE AN EXTRA LAYER OF SECURITY FOR YOUR

   PRIVATE KEYS. https://developer.apple.com/documentation/security/certificate_key_and_trust_services/keys/ storing_keys_in_the_secure_enclave

10. SECURE ENCLAVE • A part of A7 and newer chips

    • Secure Enclave Processor (SEP) is separate from Application Processor (AP) • Shares the RAM with AP but encrypted (TZ0) • SEP has its own OS

11. SECURE ENCLAVE • Stores only 256-bit elliptic curve private keys

    • Can’t import preexisting keys You can create private key, store it and perform operations on it.

12. • Biometry is stored on device as mathematical representation •

    It is encrypted with a private key stored in Secure Enclave • Biometry data is used by Secure Enclave only • It can’t be accessed by OS or any application

13. LocalAuthentication • Specify a particular policy and user message •

    The framework coordinates with Secure Enclave • Validation returns boolean value

14. LocalAuthentication • Specify a particular policy and user message •

    The framework coordinates with Secure Enclave • Validation returns boolean value WARNING

15. LAContext *myContext = [[LAContext alloc] init]; NSError *authError = nil;

    NSString *myLocalizedReasonString = @"For Securing App with TouchID"; if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) { [myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:myLocalizedReasonString reply:^(BOOL) success, NSError *error) { if (success) { // User authenticated successfully } else { // User failed to authenticate successfully } }]; } else { // Could not evaluate policy https://nvisium.com/blog/2016/06/22/dont-touch-me-that-way.html LocalAuthentication

16. LAContext *myContext = [[LAContext alloc] init]; NSError *authError = nil;

    NSString *myLocalizedReasonString = @"For Securing App with TouchID"; if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) { [myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:myLocalizedReasonString reply:^(BOOL) success, NSError *error) { if (success) { // User authenticated successfully } else { // User failed to authenticate successfully } }]; } else { // Could not evaluate policy https://nvisium.com/blog/2016/06/22/dont-touch-me-that-way.html LocalAuthentication

17. LAContext *myContext = [[LAContext alloc] init]; NSError *authError = nil;

    NSString *myLocalizedReasonString = @"For Securing App with TouchID"; if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) { [myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:myLocalizedReasonString reply:^(BOOL) success, NSError *error) { if (success) { // User authenticated successfully } else { // User failed to authenticate successfully } }]; } else { // Could not evaluate policy https://nvisium.com/blog/2016/06/22/dont-touch-me-that-way.html VULNERABLE AGAINST REVERSE ENGINEERS LocalAuthentication

18. LAContext *myContext = [[LAContext alloc] init]; NSError *authError = nil;

    NSString *myLocalizedReasonString = @"For Securing App with TouchID"; if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) { [myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:myLocalizedReasonString reply:^(BOOL) success, NSError *error) { if (success) { // User authenticated successfully } else { // User failed to authenticate successfully } }]; } else { // Could not evaluate policy https://nvisium.com/blog/2016/06/22/dont-touch-me-that-way.html VULNERABLE AGAINST REVERSE ENGINEERS LocalAuthentication USABLE PAYLOAD

19. KEYCHAIN

20. KEYCHAIN • A database storing encrypted items • Good for

    storing passwords, tokens, not for files • Each item is protected by passcode/biometry and device secret • Keychain items are available when user authenticates to the device
21. None

22. THE CORRECT FLOW EXAMPLE • The user secret is stored

    in Keychain. • When the protected action is triggered, Keychain should be unlocked with Touch ID to get the secret. • BE should enforce the client to include that secret when the protected action is performed.

23. THE CORRECT FLOW EXAMPLE • The user secret is stored

    in Keychain. • When the protected action is triggered, Keychain should be unlocked with Touch ID to get the secret. • BE should enforce the client to include that secret when the protected action is performed. WHAT ELSE CAN GO WRONG?

24. KEYCHAIN • Accessibility and authentication rules

25. KEYCHAIN • Accessibility and authentication rules SecAccessControlRef • kSecAccessControlTouchIDAny –

    Use any of the registered fingerprints • kSecAccessControlTouchIDCurrentSet – Use the current set of fingerprints when data saved to keychain. If current set changes, the TouchID evaluation fails.
26. None

27. ANY VULNERABILITIES IN SECURE ENCLAVE?

28. https://twitter.com/xerub/status/897896081874329600 HACKER CLAIMS TO HAVE DECRYPTED SECURE ENCLAVE

29. https://twitter.com/xerub/status/897896081874329600 HACKER CLAIMS TO HAVE DECRYPTED SECURE ENCLAVE

30. https://youtu.be/ei6NWGfRs2o Apple Secure Enclave Processor Hack Explained • Firmware decryption

    key for iPhone 5s only

31. IS IT SECURE? ★ Chance that someone else fingerprint will

    unlock you device is 1 in 50 000 ★ For Face ID it is 1 in 1 000 000 https://images.apple.com/business/docs/FaceID_Security_Guide.pdf

32. IS IT SECURE? ★ Chance that someone else fingerprint will

    unlock you device is 1 in 50 000 ★ For Face ID it is 1 in 1 000 000 ★ To compare: 4 digit passcode has 1 in 10 000 chance while 6 digit passcode has 1 in 1 000 000 https://images.apple.com/business/docs/FaceID_Security_Guide.pdf

33. TOUCH ID AND FACE ID ARE VULNERABLE AGAINST TARGETED ATTACKS

    https://youtu.be/2u4ZLGsw1zo
34. None

35. WHERE TO GO NEXT OWASP MSTG – Testing Local Authentication

    https://github.com/OWASP/owasp-mstg/blob/master/Document/0x06f-Testing-Local- Authentication.md iOS Security Guide https://www.apple.com/business/site/docs/iOS_Security_Guide.pdf WWDC 14 – Keychain and Authentication with Touch ID https://devstreaming-cdn.apple.com/videos/wwdc/ 2014/711xx6j5wzufu78/711/711_keychain_and_authentication_with_touch_id.pdf David Lindner – Don’t Touch Me That Way https://nvisium.com/blog/2016/06/22/dont-touch-me-that-way.html

36. https://speakerdeck.com/julep/ owasp-mstg-in-real-life https://speakerdeck.com/julep/owasp- mstg-when-authentication-goes-wrong OTHER TALKS https://www.facebook.com/julia.potapenko.16 https://t.me/OWASP_ZHYTOMYR_CHAT

37. THANK YOU!