Ukraine's IT Army, a volunteer cyberwarfare group, said it had targeted Russian banks and Russia's Mir payment system on June 20, rendering a range of services "non-functional."
The Mir payment system was instituted following Russia's illegal annexation of Crimea in 2014 after international sanctions began to limit the usage of international cards.
Its usage increased after the beginning of the full-scale invasion of Ukraine in 2022 and the subsequent withdrawal of the major card issuers Visa and Mastercard from Russia.
"When we promised yesterday to take down the enemy banking system, those weren't empty words," the IT Army said in a post on Telegram.
According to the group, the attack disconnected the Mir payment system and affected banks, including VTB, Alfa-Bank, Gazprombank, Sberbank, "and many smaller services."
"This is possibly the largest DDoS (distributed denial-of-service) attack in history," the group said.
According to the Russian state-controlled newspaper Vedomosti, reports that Mir had stopped working emerged at around 10 a.m. local time.
The DDoS attack "affected the services of banks and third-party companies" and reached its peak at around 2 p.m. local time, before being repelled, Vedomosti said.
A previous attack by the IT Army disrupted the fare payment system in Moscow and Kazan public transport.
The Kyiv Independent news desk
