Over the last week, the hackers successfully erased vast amounts of data from companies like OrbitSoft, a software firm closely associated with the Russian army, and Orient Systems, a supplier of navigation equipment to Russian military manufacturers, particularly those producing unmanned aerial vehicles.

In the case of OrbitSoft, over 100 terabytes of data were deleted. Additionally, the hackers targeted 19 servers of internet providers in the city of Nizhny Novgorod, erasing all data and sending subscribers messages warning of “inevitable retribution” for Russia’s actions in Ukraine.

The attack was carried out by activists from the BO_Team cyber community, collaborating closely with experts from Ukraine’s Main Intelligence Directorate of the Ministry of Defense.

The cyberattack comes just days after Ukraine’s IT Army, a volunteer cyber warfare group, launched a similar attack targeting Russian banks and the Mir payment system, which was established in 2014 following Russia’s illegal annexation of Crimea as a response to Western sanctions that limited the use of international payment cards in Russia.

Ukraine’s IT Army claimed to have disrupted the system, affecting numerous banks, including VTB, Alfa-Bank, Gazprombank, and Sberbank. The group described this operation as potentially the largest DDoS (distributed denial-of-service) attack in history.

A DDoS attack disrupts the normal functioning of a targeted server, service, or network by overwhelming it with a flood of internet traffic.