Ukrainian cyber units hacked into thousands of servers of Russia's tax system, extracting sensitive information before destroying the tax database, Ukraine's military intelligence (HUR) said on Dec. 12.
The news follows reports on Nov. 29 that HUR orchestrated the hacking of television channels in Crimea to broadcast a speech by President Volodymyr Zelensky and that the Security Service of Ukraine (SBU) hacked into the website of Russia's Labor Ministry.
According to HUR, defense ministry and military intelligence cyber units hacked into the central server of the Federal Tax Service, as well as 2,300 regional servers in Russia and Russian-occupied Crimea, infecting them with malware.
The entire database of the tax system was destroyed, as well as backup copies, HUR said. Intelligence suggests that "Russia will not be able to fully resuscitate its tax system."
The Russian IT company Office.ed-it.ru, which operated a database of the Federal Tax Service, was also a victim of a similar attack.
The hacks resulted in the "complete destruction of the infrastructure of one of the main state bodies" of Russia and revealed a multitude of tax data, which is now in the hands of Ukraine, HUR said.
HUR did not specify the exact date of the hack but said that Russia has "been unsuccessfully trying to restore the work of the Russian tax authorities for the fourth day in a row."
Experts estimate that the Federal Tax Service will not be functional for "at least a month."
The news comes after a "massive" hacker attack was reported on Dec. 12 by Monobank, one of Ukraine's largest banks, and telecommunications company Kyivstar.
Russia has been repeatedly accused of backing cyber-crime groups in attacks against its rivals. Moscow has also deployed its cyber capabilities against Ukraine, including attacks on government institutions, the defense sector, and energy infrastructure.