Comment by nine_k

Technically this attack is not overly sophisticated. The hard part is knowing right people, long chains of right people, motivation, timing, that kind of thing.

No agency in their right mind will even hint on whether they are capable of doing such things or not. Any whiff of information may put their people in mortal danger. They neither confirm nor deny. The fewer people know the better. The rest of the world learns about such operations by suddenly facing their results.