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A tale of two sides of 2FA

January 31, 2020

A tale of two sides of 2FA

Two-factor/Multi-factor authentication (2FA/MFA/whatever your choice of acronym) is an important security pillar in any application, but sometimes it fails us as users and developers. How you use and implement 2FA can have huge impacts on how secure it will be, and the protection it ultimately provides.

Finding best practices about implementing 2FA can be difficult. Learn from a real world implementation, and come out knowing how to protect yourself and how to not let down your users.


January 31, 2020

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  1. @tech_christine A tale of two sides of 2FA It can

    be the best of security, or the worst of security
  2. @tech_christine What you will learn ✓ What is 2FA/MFA ✓

    How to secure your accounts ✓ What are the 2FA types ✓ How to protect users and secure an application ✓ Potential testing steps ✓ 2FA development best practices "...it was the age of wisdom, it was the age of foolishness..."
  3. @tech_christine Taking notes or pictures Asking stupid questions https://christine-seeman.com/talks Things

    you don't need to worry about "...it was the epoch of belief, it was the epoch of incredulity..."
  4. “ @tech_christine We learned that SMS-based authentication is not nearly

    as secure as we would hope, and the main attack was via SMS intercept Christopher Slowe Reddit chief technology officer and founding engineer August 2018
  5. @tech_christine What is authentication? The process of verifying that someone

    or something is the actual entity that they claim to be. - OWASP.org (these people know what they are talking about when it comes to security)
  6. @tech_christine ... but what are the different factors of auth?

    1. Factor is knowledge (i.e. your password) 2. Is the other method choice - Possession (token/soft token) - Identity (biometrics)
  7. @tech_christine If SMS wasn't bad enough •SS7 (network shared by

    every telecom) has it's own vulnerabilities •Text messages that are sent can be intercepted
  8. @tech_christine Let's figure out all the ways to hack it...

    1. Sim-swap (aka what just happened to us) 2. Port-out scam 3. Brute force on the application itself 4. Exploit SS7 weakness
  9. @tech_christine Time-based One Time Password aka app based aka soft

    token • Authy • Google Authenticator • 1Password TOTP
  10. @tech_christine Email • Convient • Should only be used with

    verified emails • Less Common, may be in use but not referred to as 2FA
  11. @tech_christine Token based Physical keys that can auth • USB

    drive • near-field communication • Many use U2F (Universal 2nd Factor)
  12. @tech_christine OTP U2F • User has physical device • Strong

    security from public key cryptography • No personal information associated with a key • Users type in codes • Set up and provision required • Secrets stored, providing a single point of attack
  13. @tech_christine Secure Your Account 1. Use long password/passphrase 2. Secure

    with alternate authentication method 3. Use a VOIP number 4. Don't reuse passwords 5. Pin/password protect phone provider Keep on being @awesome
  14. @tech_christine But wait... Now you are the developer at jiffygram

    (an insta rival) How do you secure your users from all the bad stuff out there?
  15. @tech_christine Back to your security basics 1. Strong passwords/passphrase #

    2. Don't make them be rotated 3. Store the hash securely 4. Only store sensitive data that you need ⛔
  16. @tech_christine Why this helps •Greater entropy = harder to brute

    force the password •Passwords should be hard to guess, but easy to remember •Extra length + randomness allows for more entropy (strength)
  17. @tech_christine Let's talk about password hash encryption • Just an

    algorithm that takes data and produces fixed-size output • Some hashes are stronger then others • MD5/SHA-1 = + • SHA-256/512-bit SHA-2= , • If possible with performance, use an adaptive one- way function
  18. @tech_christine ...a user lost their phone/app access/token • Recovery codes

    to the rescue! - • Allows access to application • Shown once, used once
  19. @tech_christine Code example in Ruby login_request if retries <= max_retries

    retries += 1 sleep (retries + rand(100)/1000) retry else raise "You've hit your max retries!" end
  20. @tech_christine ✓ Make it easy opt in ✓ Make it

    easy to add ✓ Make it visible ✓Make it flexible
  21. @tech_christine • For editing/removing of 2FA require credentials • If

    authentication does fail, be generic in error response Moar authentication
  22. Not this "Login for User foo: invalid password" "Login failed,

    invalid user ID" "Login failed; account disabled" "Login failed; this user is not active"
  23. @tech_christine 2FA can help but... • Can only improve security

    if you are following secure password practices • Some 2FA methods are more secure then others
  24. @tech_christine Thanks for having me NDC {London}! All the organizers

    and volunteers deserve 2 2 2 Tyson Reeder for the final graphic @tysondreeder For references and further reading checkout christine-seeman.com/talks
  25. @tech_christine QR Code Rendering https://github.com/whomwah/rqrcode ROTP: TOTP https://github.com/mdp/rotp Twilio Ruby

    API https://www.twilio.com/docs/libraries/ruby Auth Ruby API https://github.com/twilio/authy-ruby