This latest attack does not appear to be linked to the Google intrusion, said Amit Yoran, NetWitness’s chief executive. But it is significant, he said, in its scale and in its apparent demonstration that the criminal groups’ sophistication in cyberattacks is approaching that of nation states such as China and Russia.

The attack also highlights the inability of the private sector — including industries that would be expected to employ the most sophisticated cyber defenses — to protect itself.

“The traditional security approaches of intrusion-detection systems and anti-virus software are by definition inadequate for these types of sophisticated threats,” Yoran said. “The things that we — industry — have been doing for the past 20 years are ineffective with attacks like this. That’s the story.”