The Ukrainian Blackjack hacker group, possibly linked to the Security Service of Ukraine (SBU), carried out a cyber attack against the Moscow Internet provider M9 Telecom, Ukrinform reported on Jan. 9, citing an undisclosed source in law enforcement.
The report comes almost a month after a massive Russian-linked cyberattack against the Ukrainian phone operator Kyivstar, which caused massive internet and network outages across the country.
The alleged Ukrainian attack against M9 Telecom destroyed the provider's servers, deleting about 20 terabytes of data, which included the company's official website, branch websites, mail server, and cyber protection services, according to the source.
At the time of publication, the official website of M9 Telecom was operational.
As a result of the attack, some Moscow residents were left without access to the internet and television, Ukrinform, a Ukrainian state-run media outlet, wrote.
The SBU has not officially reported on the attack. The service's spokesperson has not replied to the Kyiv Independent's request for comment.
The Ukrinform's source allegedly said the attack was just a "warm-up" for the hackers who are preparing a bigger one, which will be a "serious revenge for Kyivstar."
The Blackjack hacker group also downloaded over 10 gigabytes of data from the company's mail server and client databases, making them publicly available, added Ukrinform.
The group previously conducted a cyber attack against Rosvodokanal, a Russian water utility company, likely also with the support of the SBU, anonymous sources told Ukrainska Pravda on Dec. 20.
Ukraine came under a massive cyberattack on Dec. 12, which targeted Kyivstar, the largest telecommunications provider, and one of the country's most important banks, Monobank.
People across the country reported internet and network outages, as well as issues with air raid alerts.