From the reliable Center for Public Integrity:
The existence of such a plan means that America is more fully integrating offensive cyber attacks into its overall military planning systems, a move likely to make cyber combat more likely and eventually more commonplace, sometimes without first gaining specific presidential approval. Cyber attacks are now on a more obvious path, in short, to becoming a regular currency of warfare.
The report raises–but does not answer–a key question about cyber deterrence.
If the purpose of retaliation is to impose pain that forces the enemy, in this case Russia, to change its behavior, what countermeasures would be effective? No one really knows, since this a new kind of warfare.
What’s clear is that the rule of engagement have been relaxed. Obama had an elaborate multi-agency approval process for offensive cyber operations. Trump has loosened the reins.
While some officials and cyber experts have said that certain offensive cyber operations risk violating international law, because of the possibility they might cause collateral damage and harm civilians outside target networks, government lawyers have approved the new approach after deciding that letting the military hack into a foreign system is not an act of war, so long as a cyber weapon hasn’t yet been emplaced and the specific system being targeted isn’t actually destroyed.
Source: The Pentagon has prepared a cyber attack against Russia | Center for Public Integrity