~/talk

(Benford's) Law and Order (Fraud)

Talkat PyCon Australia 2014 · 2014-08-01..08-05· [web-performance, security]
speakerdeck:rhyselsmore
slides:none on file

Claims that email-username features plus simple models stop most abuse: a custom Sleuth pipeline extracts ~200 features (hex ratio, trigram engram gaps, digit counts, keyboard spread), stores counts in Redis, scores with an online native Bayes classifier, and acts via the Heroku API over a websocket feed. It flags and suspends in about 2 seconds, achieves ~76% detection with 1.5% false positives, and led to ~50,000 suspensions since August.

AI-written summary · about

  1. 0:00Intro
  2. 1:15Assess the situation
  3. 2:11Stories are good
  4. 3:17Some pretty cool uses.
  5. 3:50HEROKU SECURITY OFFICE 650 7TH ST, SAN FRANCISCO THURSDAY, AUG 16, 2013
  6. 4:22Run an app for $0
  7. 4:400.1% of bad users have a credit card
  8. 5:06End-users don't read the TOS
  9. 6:41We offer a shell
  10. 6:57Really easy to sign up
  11. 8:15Static Rules = Hard to maintain
  12. 8:27IP Restrictions = Too Hard
  13. 8:47Manual Hunting = Unscalable
  14. 8:58Manual verification?
  15. 10:02Characterset Switches
  16. 11:25100% Hex Characters = Hash?
  17. 14:31% missing n-grams % bad n-grams Risk Score (0 - 100)
  18. 15:24200+ features
  19. 15:40Keyboard Spread
  20. 16:20My tips for feature extraction?
  21. 17:06Shows us where the action is
  22. 17:29Operates using (almost) online models
  23. 17:54All we need to do is maintain a count of bad vs. good users
  24. 18:14We also need to maintain a count of the distinct feature:value pairs for bad vs. good users
  25. 20:10Shows a users network
  26. 20:46Gives Platform Wide Context
  27. 21:20BLOCKING BAD BEHAVIOR
  28. 22:39CURRENT ISSUES
  29. 23:07Memory usage
  30. 24:22Feature selection
  31. 24:50Team co-ordination
  32. 25:28The occasional mis-classification
  33. 25:46Doesn't stop good looking emails
  34. 26:13Different Algorithms
  35. 26:32CURRENT SUCCESSES
  36. 27:50Moar interesting models!
  37. 28:12Open Source some things!
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