KYIV, Ukraine — A top Ukrainian cybersecurity official said on Wednesday that a cyberattack against the websites of Ukraine’s defense ministry and army, as well as the interfaces of the country’s two largest banks on Tuesday, was the largest assault of its kind in the country’s history and it “bore traces of foreign intelligence services.”
Ukraine’s minister of digital transformation, Mykhailo Fedorov, said that “vectors of attacks were organized from different countries.”
“It is clear that it was prepared in advance, and the key goal of this attack is to destabilize, to sow panic, to do everything to create a certain chaos in the actions of Ukrainians in our country,” he told a news conference in Kyiv.
The announcement came as Russian forces were gathered on Ukraine’s northern, eastern and southern borders, a force President Biden estimated Tuesday at approximately 150,000 soldiers.
But officials are also concerned that Russia might seek to destabilize the country in other ways, including through cyberwarfare.
The websites and banks targeted on Tuesday evening were hit with a distributed denial-of-service attack, or DDoS, during which hackers flood the servers hosting a website until it becomes overloaded and shuts down.
Tuesday’s hack was the largest attack of that kind the country has faced, Mr. Fedorov said.
While a full investigation is underway, all signs pointed to Russia, said Ilya Vityuk, the Head of the Ukrainian Intelligence Agency’s Cyber Security Department.
“We know today that, unfortunately, the only country that is interested in such strikes on our country, especially against the background of mass panic over a possible military invasion is, unfortunately, the Russian Federation,” he said during the news conference.
He added that the attack likely cost “millions of dollars” to execute it, far beyond the capabilities of individual hackers or groups.
“Such attacks are usually perpetrated by countries,” he said. “Such attacks need infrastructure.”
Mr. Vityuk said that the attack bore similarities to a mid-January attack in which hackers brought down dozens of Ukrainian government websites, including that of Ukraine’s Ministry of Foreign Affairs.
At the time, a message on the Ministry of Foreign Affairs warned: “Ukrainians! All your personal data was uploaded to the internet. All data on the computer is being destroyed. All information about you became public. Be afraid and expect the worst.”
On Tuesday, clients of the state-owned PrivatBank and Oschadbank began to complain about difficulties using teller machines and mobile phone applications. The banks confirmed the attack, but said the funds in users’ accounts had not been affected, though users said they had been temporarily unable to withdraw money or use their credit cards. Some clients of the banks were worried, as their bank balances appeared drained. By Tuesday evening that most services had been restored.
Pavlo Kukhta, an adviser to Ukraine’s energy minister, said in an interview that the hackers were possibly preparing for a larger attack, which could target the country’s “vulnerable” power grid.
“The goal is quite simple: to sow panic, show what they are capable of, test the systems and see if they are vulnerable,” he said. “They are poking around and looking for weaknesses.”