Russia launches war's biggest cyberattack against Ukrainian mobile operator

Attack has affected air raid alert systems near Kyiv

Russia has attacked and partially destroyed the IT network belonging to Kyivstar, Ukraine's largest mobile operator.

The attack, which CEO Oleksandr Komarov said was "a result" of the war with Russia, has disrupted communications for the more than half of Ukraine's population who use Kyivstar to stay connected.

The damage has not only knocked out regular mobile networks. It has also affected IT infrastructure and, says Reuters, 'put millions of people in danger of not receiving alerts of potential Russian air assaults.'

Ukrainian officials said the cyberattack affected air raid alert systems in more than 75 settlements near Kyiv. Alerts are now being announced through loudspeakers until repair work is completed.

In an appearance on national television, Komarov said, "[The attack] significantly damaged [our] infrastructure, limited access, we could not counter it at the virtual level, so we shut down Kyivstar physically to limit the enemy's access."

He added that users' personal data was safe.

Kyivstar has partially restored its fixed-line broadband services and is working to recover other services.

Russia's Killnet group, which has previously attacked organisations in Lithuania, shut down US airport websites and tried to disrupt last year's Eurovision song contest, has claimed responsibility on Telegram. However, it provided no evidence.

Ukraine's SBU intelligence agency has told Reuters it is still investigating the possibility of the attack having come from Russia's security services. A source has also told the publication it "definitely" came from a state actor.

The source said data cable interception showed "a lot of Russian controlled traffic directed at these networks." Killnet, notably, is known for its DDoS attacks.

"There's no ransom. It's all destruction. So it's not a financially motivated attack," the source added.