Cyber-attacks on Ukraine are conspicuous by their absence

dog that has yet to bark. Russia’s invasion of Ukraine has been fought with all sorts of high-tech weapons, from cruise missiles and helicopters to armed drones and a public-relations battle on . Conspicuous by its absence, though, has been something that many observers thought would be one of the defining features of a 21st-century conflict between high-tech opponents. “Cyber-attacks” aimed at Ukrainian computer systems seem to have played hardly any role. That is a puzzle. Computer systems run more and more of modern society, and are riddled with bugs and inadvertent weaknesses. These can be exploited by attackers with grave consequences in the material world. In 2015 Russian hackers managed to knock out power for around 230,000 customers in western Ukraine. The attackers repeated the trick the following year. In 2017 another Russian attack featuring a piece of malware dubbed “NotPetya” disrupted Ukrainian airports, railways and banks.