Researcher Barred From US

Halvar Flake, a speaker at this week's Black Hat conference, has been denied entry into the United States following the discovery of his presentation in his travel materials.

Flake, a pseudonym for Thomas Dullien, CEO and head of research at Sabre Labs, was scheduled to give a two-day training course on analyzing security vulnerabilities. But according to his blog, authorities had other ideas. (See X-Ray Vision for Bug Finders and 10 Hot Security Startups.)

"For four and a half hours I was interviewed about who exactly I am, why I am coming to the U.S., what the nature of my contract with Black Hat is, and why my training class is not performed by an American citizen," Flake writes. "After four hours, it became clear that a decision had been reached that I was to be denied entry to the U.S., on the grounds that since I am a private person conducting the trainings for Blackhat, I was essentially a Black Hat employee and would require an H1B visa to perform two days of trainings in the U.S."

Flake says he chose to present as a private individual instead of as an employee of his company because he had signed the deal with Black Hat years ago, before his company was formed, "and never got around to changing it." But customs officials said he cannot work for Black Hat without the proper visa. Flake says he has done many training courses in the U.S. before and has never been stopped by immigration.

Dullien was forced to return to Germany, where he plans to apply for a U.S. business visa.

"I need to wait until the American consulate opens, and then apply for a business visa. I have not been able to determine how long this might take -- estimates from customs officials ranged from 'four days' to 'more than six weeks,' " he writes.

— Tim Wilson, Site Editor, Dark Reading