Take away their toys
These people know or should know that the only reason cyber-warfare is even 'a thing' at this level is because they refuse to make the network properly secure.
The problem those agencies have with a secure network is that it protects the network against *them*.
We could have m of n voting to allow access to information so we could deal with pedophiles without compromising legitimate security.
The only reason cyber-warfare like this is even possible is that the warmongers are in charge of the networks and have made an unsafe war zone out of our public networks.
We can and I hope will move to a 'darknet' that makes it impossible to wage DOS attacks, to spy on people, to mount successful MIM attacks and eventually to even interfere with the infrastructure. We can help 'fast-track' this switch by making it illegal to wage war against the citizens of the network, including interfering with standards.
Protect against SPAM and DOS by charging up-front for traffic and possibly refunding when the recipient acknowledges it was legit.
Protect against spying by providing for genuinely effective encryption, encrypting all traffic, making routing distributed so compromised routers cannot compromise the network.
MIM attacks don't work if the network is secure and proper encryption is in place.