According to the government of Ukraine and major cybersecurity firm, Russian military hackers attempted and failed last week to hack Ukraine’s energy infrastructure.

According to Ukraine, this attack was intended to steal computers from multiple substations. Then, it would delete all files and shut down the infrastructure. summary of the incident.

ESET is a cybersecurity firm based in Slovakia that works to secure the infrastructure of Ukraine. summary of the attack that it was conducted by the same arm of Russia’s military intelligence agency, GRU, that had previously successfully executed similar attacks in 2014 and 2015. Both incidents involved residents from Kyiv. temporarily lost power. ESET stated that the attack was planned at least for two weeks.

Ukraine has not suffered from any visible damage since Russia’s invasion of Ukraine in February. Multiple “wiper attacks” have been launched against Ukraine, which include those targeting computers within the government and financial institutions as well as internet service providers. These attacks target files that have been hacked and also seek to delete them all.

Viktor Zhora is a senior Ukrainian cybersecurity officer. He stated that the malware infected some computers within Ukraine’s energy sector, and caused problems at one facility. He said that the malware was swiftly removed and customers were not affected by it.

Zhora explained that the combined effort of Ukrainian intelligence and Microsoft information technology staff provided the defense.

Zhora did not name the electricity company, nor the location where it operated. However, Zhora stated that they provide electricity to millions of residents.

Ciaran Martin was the ex-head of U.K.’s National Cyber Security Centre. He said that the attack is in keeping with Russian hacking attempts.

Martin stated in a text that “this is Russia’s type of operation between the annexe of Crimea in 2014, and the complete invasion this year.” This is a more rapid version of the same operation, but it’s also a much less successful one due to cyber defense.