Software King of the World Microsoft was also breached, and its products were used to further attacks on others.

The Energy Department and its National Nuclear Security Administration, which maintains America's  nuclear stockpile, were targeted as part of the larger attack, according to a person familiar with the matter.

An ongoing investigation has found the hack didn't affect "mission-essential national security functions".

Shaylyn Hynes, a Department of Energy spokeswoman, said in a statement. "At this point, the investigation has found that the malware has been isolated to business networks only." Hynes said.

In addition, two people familiar with the broader government investigation into the attack said three states were breached, though they wouldn't identify the states.

 A third person familiar with the probe confirmed that states were hacked but didn't provide a number.

In an advisory Thursday that signalled the widening alarm over the the breach, the Cybersecurity and Infrastructure Security Agency said the hackers posed a "grave risk" to federal, state and local governments, as well as critical infrastructure and the private sector. The agency said the attackers demonstrated "sophistication and complex tradecraft".

The current president Donald Trump seems to have a problem believing that Russians do any hacking.