Kiberberkut, or Cyber Berkut, accessed and published customer data from a major commercial bank co-owned by the head of the pro-government Dnipropetrovsk region.
The hacktivist group announced the breach on July 4 on Vkontakte, Russia’s rendition of Facebook.
“The group explained in a statement that they had analyzed the tactics of another hacking group, Green Dragon, who crippled PrivatBank's website on [June 30] with a distributed denial-of-service attack,” the Moscow Times reports.
The information posted includes passport data, account information and phone numbers.
Kiberberkut claims to have exposed gaps in PrivatBank's cybersecurity and posted technical information on its Vkontake page to prove the statement.
The group had warned customers their money was at risk and urged them to transfer funds to any state-owned bank.
"PrivatBank in May became a target for pro-Russian separatists in Eastern Ukraine after the bank suspended its operations in the restive cities of Donetsk and Luhansk,” and billionaire Igor Kolomoisky was appointed Dnipropetrovsk’s governor, according to the Moscow Times. “One of his first acts as governor of the region was to place a $10,000 bounty on the heads of Russian ‘saboteurs’ fighting in the region.”