For better or for worse, warfare drives technology innovation. World War I turned the airplane from a rickety contraption into an essential force in battlefield dominance; World War II brought us jet planes, radar, and atom bombs. Today, attacks come through the Internet, not from the sky—and so do the responses.

The cyberattack offensive that Russia launched in Ukraine in 2014 introduced a new doctrine, hybrid warfare, that blends special-forces military action, sophisticated propaganda, social media manipulation, and hacking. And the resistance is coming from volunteers who work together.