For the second year running, Nir Goldshlager is the No. 1 name in Facebook’s security “hall of fame”. Goldshlager uncovered a major security flaw that allowed hackers to take control of accounts. When Facebook fixed the breach, Nir discovered a second major problem in the “corrected” code.
http://www.timesofisrael.com/the-israeli-hacker-who-saved-facebook-twice/