Ukraine’s Largest Mobile Operator Knocked Out in Cyberattack, Millions Lose Phone and Internet Service

LATEST: Everything We Know About the Kyivstar Cyber-Attack

Ukraine’s largest mobile operator, Kyivstar, was taken down by a cyberattack on Tuesday morning, resulting in some 24.3 million subscribers losing their phone and internet service, while shops throughout the country were unable to process credit payments.

In Lviv, street lights continued to burn through the morning as the remote switching is controlled through a Kyivstar network. The malfunction meant all disconnections of power to the lights had to be done manually.

“The company's specialists are working on eliminating the problem. We apologize to subscribers for the temporary difficulties and thank you for your understanding,” Kyivstar wrote on its Facebook page.

Ukraine's security service said it was probing the attack.

“The Security Service of Ukraine (SBU) has opened criminal proceedings into a cyber attack on one of the national mobile operators, Kyivstar,” the SBU said. “One of the versions currently being investigated is that the special services of the Russian Federation may be behind this hacker attack.”

By about 1 p.m. on X, Kyivstar announced that the technical failure that took down its network was “a powerful hacker attack.” 

Ukraine’s main phone operator denounced the act of “war.”

“This is a war, it takes place not only on the battlefield, it also takes place in virtual space and unfortunately, we are affected as a result of this war,” Kyivstar’s general director said on national television.

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Kyivstar users were unable to make or receive calls and use internet services. Kyivstar’s network is also essential for payment systems in most shops.

That said, users’ personal data was not compromised, the company wrote on X.

The company's mobile applications were also temporarily unavailable.

Authorities of the northeastern city of Sumy said the air raid alert system “will not work temporarily,” AFP reported.

PrivatBank spokesman Oleg Serga said its banks and cash terminals were partly disrupted, according to public broadcaster Hromadske. 

Meanwhile, one of Ukraine's biggest banks, Monobank, said it had been targeted by a “massive DDoS attack,” its co-founder Oleg Gorokhovsky said on Telegram.

Kyivstar’s takedown is perhaps the largest successful cyberattack on Ukraine since Russia launched its Feb. 24, 2022, full-scale invasion.

Russia continues to use its cyber capabilities to support its invasion of Ukraine, but hasn’t had many big wins, Viktor Zhora, the deputy head of the State Service of Special Communications and Information Protection of Ukraine (SSSCIP) told Kyiv Post in October.

Ukraine has a powerful “IT Army” of its own which has generally been good at foiling the worst Russian cyberattacks.