We did most of the inventing and building of the internet. How the hell can't we overwhelmingly dominate the online, wild-west, no-convention-restriction aspect of these conflicts? What are we waiting for?
In all honesty, there is a limited number of exploits that the government knows about while others do not. Supposedly.
So you have to be careful about what you do and how you do it.
Remember the Iranian centrifuges that kept failing and delaying Iran's ability to acquire weapons grade fission materials? That was due to a hack that the US had implemented, but they were using it in a very controlled manner which was baffling the Iranians. Then the US provided the info to Israel, and the Israelis were not as willing to use the code as slowly as the US was. So Israel starts causing more and more frequent failures, and that is when Iran figured out what was happening.
Just because things are not being reported or known doesn't mean that things are not going down. And the same is true in reverse. It is inevitable that if we perform an action that the Soviets....err...Russians will launch an attack of their own. I know we hear about attacks from Russia and China all the time, but I'm not so naive as to believe we are not continually doing the same thing to them... we just try to have things in place that they do not know about so we can use them when it is absolutely warranted.
Right now, the Ukraine is not really our battle. They did not join NATO for starters. IF Putin decides he wants more, More, MORE! and goes after a NATO member... well, that is when I would expect to see some of our cyber teams use a few of their tricks.
None of this is to say the US is better than others at cyber, just more cautious about exposing what hacks are in place.
In all honesty though, the group that I'm surprised has yet to unleash something is Anonymous. I would think this kind of event would get their passions flowing. Russia wants to do something, let a group like Anonymous initiate attacks that shut down a bunch of the shit inside Russia. Let the people lose power, lose their internet, lose communications... but let Anonymous do the dirty work such that the US itself is not considered responsible and can easily blame it on a fringe group of hackers who are well recognized for performing such attacks. And don't have only Anonymous do it, but every hacker worth their salt should shut down as much of Russia as possible. Hell, just overwhelm their entire DNS structure with DDoS attacks. Piss off the people of Russia, make it clear that it is the fault of Putin's actions. Get the people mad enough that they will revolt against him and - preferably - kill him. That said, we supposedly do not know who the leader(s) is/are of Anonymous. Their current silence makes one wonder whether they are from Russia or China.
Ah, the world of cyber is full of intrigue and mystery! The modern day spies are cyber experts for certain.