The release on websites this week of what appears to be top-secret computer code that the National Security Agency has used to break into the networks of foreign governments and other espionage targets has caused deep concern inside US intelligence agencies, raising the question of whether America's own elite cyberwarriors have been hacked and their methods revealed.
The NSA would say nothing on Tuesday about whether the coding released was real or where it came from. Its public affairs office did not respond to inquiries.
"It certainly feels all real," said Bruce Schneier, a leading authority on state-sponsored breaches. "The question is why would someone steal it in 2013 and release it this week? That's what is making people think this is likely the work of Russian intelligence."
However, the fact that the code is dated from 2013 suggests that the hackers' access was cut off around then, perhaps because the agency imposed new security measures.
