It might constitute an attack if the intruders destroyed data, for example, or used their access to do damage in the physical world, say, by shutting down power grids. But breaking into unclassified government and corporate networks? Reading other people’s emails? That’s spying.

“I don’t think under anybody’s definition who works in this field is this any kind of cyber attack,” said Gary Brown, a former Pentagon cyber official who is Professor of Cyber Law at National Defense University.

“This is really just a very successful espionage operation. It’s the kind of thing we would love to carry out. And it’s sort of a wake-up call – we have got to get better. The Russians are way better at this than we even knew about.”