Thomas Dullien, a prominent security researcher who has been a fixture at the annual Black Hat security conference, has been denied entry into the U.S. to attend and conduct training at this year's confab.
Dullien (left), a German reverse engineering whiz known in hacker circles as "Halvar Flake," said he was blocked from entering the U.S. after customs officials found printed "training materials" in his suitcase.
The CEO and head of research at Sabre Security said the denial appeared to be linked to his use of the visa waiver program to present Black Hat training as a private citizen instead of as a representative of a company.
After a nine-hour flight and a four-and-a-half hour interview with U.S. immigration officials, Dullien was put on the next 9-hour flight back to Germany and it seems uncertain he will get the visa situation straightened out in time for next week's Black Hat show.
Dullien has attented and presented at Black Hat for the last seven years and, even before that, he has been part of the training sessions -- teaching reverse-engineering and hacker tricks to mostly U.S.-government related folks, mostly working on US National Security in some form.
"I have trained people from the DoD, DoE, DHS and most other [government] agencies that come to mind," Dullien explained.
He has also presented at Microsoft's internal "Blue Hat" conference and is considered one of the most respected researchers in the world.
See more on Dullien's nightmare on his personal blog.