The Channel logo


By | John Leyden 30th July 2007 11:02

US denies entry to security researcher

Fear of a Black Hat

A high profile security researcher has been refused entry to the US on the way to this year's Black Hat security conference over "visa irregularities".

Reverse engineer Thomas Dullien (better known by his nom de guerre Halvar Flake), and a long-time fixture of the Black Hat conferences, reports that he was denied entry to the US on a technicality.

Dullien has a contract with Black Hat Consulting to offer training at the show as an individual, not through the German start-up firm he founded. Because of this, customs officials refused to allow him permission to enter the country and sent him on the next plane back to Germany - following a four hour interview.

The white hat hacker has been offering training classes at Black Hat for six years without problem, always telling US immigration that he was coming to the US to present at a conference and hold a training class. This time around a routine customs search, which prompted questions about the training materials he carried, led to further questions that eventually led to his expulsion.

Dullien will need to obtain an H1-B visa if he wants to offer training at Black Hat USA in future. And, after being denied entry to the country under the scheme, he'll no longer be eligible for entry under the visa waiver programme the US extends to European citizens, even if he travels to the country on holiday. Ironically, as Dullien points out, most of the attendees at his training sessions are US government employees.

As a European citizen, Dullien (of course) faces no paperwork barriers in offering the same training service at Black Hat Europe. ®

comment icon Read 21 comments on this article alert Send corrections


Frank Jennings

What do you do? Use manual typwriters or live in a Scottish croft? Our man advises
A rusty petrol pump at an abandoned gas station. Pic by Silvia B. Jakiello via shutterstock

Trevor Pott

Among other things, Active Directory needs an overhaul
Baby looks taken aback/shocked/affronted. Photo by Shutterstock

Kat Hall

Plans for 2 million FTTP connections in next four years 'not enough'
Microsoft CEO Satya Nadella


Suit-and-tie-wearing man tries to meditate, take deep breaths in faux yoga pose. Photo by Shutterstock
Emotional intelligence, not tech skills, is the way to woo suits
League of gentlemen poster - Tubbs and Edward at the local shop. Copyright BBC
One reselling man tells his tale of woe