NATO is so unprepared for a cyber attack that the group of experts it assembled to write about cyber espionage can't definitively say whether it's legal or not. As the NATO Cooperative Cyber Centre of Excellence report put it, "cyber espionage, as a general matter, does not violate international law."
Why it matters: Countries under attack are paralyzed to defend themselves since the definition of a lawful response is unclear. That leaves NATO's responses to cyber attacks on member countries at a standstill.
