Cyberattack in Ukraine war affected thousands across Europe

A cyberattack targeting a satellite network used by Ukraine’s government and military agencies shortly after Russia’s invasion also knocked offline tens of thousands of broadband internet users across Europe, the satellite owner disclosed Wednesday.

The owner, U.S.-based Viasat, provided new details of how the cyberattack, the biggest known such attack in the war so far, was conducted and its wide-ranging impact. The attack affected users from Poland to France and knocked off remote access to thousands of wind turbines in central Europe.

Viasat did not say in its statement who it believed was responsible for the attack. Ukrainian officials have blamed Russian hackers.

The Viasat attack, coming just as Russia was launching its invasion, was considered at the time by many a harbinger of a wave of serious cyberattacks extending beyond Ukraine. But, so far, those attacks haven’t materialized, though security researchers say the most impactful war-related cyber operations are likely occurring in the shadows. A free-for-all of lesser attacks, many apparently carried out by volunteers, have been carried out.

The attack though highlighted how satellite technology that serves both military and non-military clients can be targeted in a conflict, with the impact felt by individuals and businesses far from the battlefield.

The attack in the early hours of Feb. 24 on the KA-SAT satellite network began with a distributed denial-of-service onslaught knocking offline a large number of modems. It then moved to a destructive attack in which a malicious software update distributed across the network rendered tens of thousands of modems across Europe inoperable by overwriting their internal memory, Viasat said.

It said it has shipped 30,000 replacement modems to affected customers across Europe, most of whom use the service for...