Ukraine says it attacked Russia’s tax service

Ukraine’s defense intelligence directorate (GUR) has claimed that its hackers infected thousands of servers belonging to Russia’s IRS equivalent, the Federal Taxation Service (FTS), and destroyed backups.

Kyiv’s attack allegedly penetrated the FTS’s central server as well as 2,300 regional servers, covering the entire 11-time zone-spanning country. GUR claims that malware was deployed in every affected server.

According to a Russian business news outlet Kommersant, the FTS denied the attack had any impact on its daily operations, saying GUR's statements do not reflect the reality.

The GUR's attack supposedly also targeted Office.ed-it.ru, a Russian IT company servicing the country’s digital infrastructure. GRU claims that Ukraine’s hackers took over FTS and Office.ed-it.ru configuration files, allowing them to destroy databases and any backup they had.

GUR claims that the attack paralyzed communications between the FTS’s central headquarters in Moscow and its regional departments, crippling Moscow’s taxation procedures. Additionally, the attack is claimed to have netted Kyiv all of Russia’s tax data.

In late November, Ukraine took credit for attacking Russia’s aviation agency. At the time, GUR said it had obtained a large volume of confidential documents from Rosaviatsiya, Russia’s Federal Air Transport Agency, “as a result of a successful complex special operation in cyberspace.”

Earlier this week, Kyivstar, one of the largest Ukrainian telecommunications companies, suffered a cyberattack that shut down internet services for millions of users.

Updated on December 13 [11:55 AM GMT]. The previous version of the article incorrectly stated that FTS did not comment the attack claims.