Intelligence officials […] have determined that [Snowden] used inexpensive and widely available software to “scrape” the National Security Agency’s networks, and kept at it even after he was briefly challenged by agency officials.
Using “web crawler” software designed to search, index and back up a website, Mr. Snowden “scraped data out of our systems” while he went about his day job, according to a senior intelligence official. […]
Through his lawyer at the American Civil Liberties Union, Mr. Snowden did not specifically address the government’s theory of how he obtained the files, saying in a statement: “It’s ironic that officials are giving classified information to journalists in an effort to discredit me for giving classified information to journalists. The difference is that I did so to inform the public about the government’s actions, and they’re doing so to misinform the public about mine.”