Sebastian Neef (aka @gehaxelt) has been involved in IT security and hacking since his early teens. While others were playing computer games, he was more interested in hacking them. During high school, he discovered bug bounty programs and quickly began to appear in several halls of fame, even reaching the Top 10 of Bugcrowd at the time.

Nowadays, he continues to pursue his PhD at the Technical University of Berlin, at the Chair for Security in Telecommunications, focusing his research on web and network security. In his spare time, he likes to play and organize CTFs as part of ENOFLAG, or do IT security freelance work.