MadHat leads DC214 (the Dallas DefCon Group) and is a member of NMRC. His paying gig is as the Manager of the Vernier Threat Labs. Before working at Vernier, Madhat was one of the core security team members for Yahoo and lead the vulnerability assessment and day-to-day security monitoring for Yahoo world wide. He has written several open source security tools and has contributed to an upcoming book on Nmap being written by Fyodor.