Leanardo Arangoncillo, a naturalized citizen from the Philippines, has been identified as the first spy to be found working in the White House in modern times. He was working in the office of Vice President Dick Cheney, and it's been reported that he passed on hundreds of documents to the Filipino government in the last couple of years. He had top secret clearance, and stole many of the documents from White House computers. This is the second major breach of standard security measures discovered during this administration. The other, involving a fake reporter who asked softball questions to the president to make him look better during press conferences, led to a media hailstorm after it was realized that the White House likely played a roll in sneaking this man in with the rest of the media pool.
ABC News: Espionage Case Breaches the White House