Both Saturday’s Eurovision grand final and two earlier semi-finals were targeted by the Pro-Russian Killnet hacker group in denial of service (DDoS) attacks, a police statement said.
Italian police said these attempts were blocked.
The contest, which was held in Italy, was seen as a public show of solidarity with Ukraine and an outpouring of anti-war feeling across Europe, with Russia banned from Eurovision earlier in the year.
In a Telegram post, Killnet hit back against the Italian authorities’ claims, saying it was not behind the attack.
“According to foreign media, Killnet attacked Eurovision and they were stopped by the Italian police, so Killnet did not attack Eurovision,” wrote the group.
The hacker group said it had now “declared war” on the Italian police, alongside ten unspecified countries, in response to the allegation.
They also implied they had taken down the website of the Polizia Postale (Postal Police) which combats cybercrime in Italy.
As of Monday afternoon, the site was unavailable outside of the country, although Euronews cannot independently verify the reason for this.
“In collaboration with ICT Rai and Eurovision TV, various computer attacks of a DDoS nature aimed at network infrastructures during voting operations and singing performances were mitigated,” the Italian authorities said.
In the same statement, Italian police added that they had seen a discussion about the attacks on Killnet’s alleged Telegram account. No further details were offered by the police.
DDoS attacks attempt to prevent websites from working properly by flooding them with traffic, much like how too many cars can clog up a normal road. If successful, DDoS attacks make websites inaccessible.
Killnet made headlines earlier this year after claiming responsibility for an attack against international hacktivist movement Anonymous, which saw its servers temporarily taken down.
This happened after Anonymous pledged to leak details of Russian troop movements and other military information following the country’s invasion of Ukraine in February.