From The Guardian:
Cyber conflicts are fought in the shadows, but in the case of Russia's invasion of Ukraine, it is a group that calls itself Anonymous that has made the most public declaration of war. Late on Thursday the hacker collective tweeted from an account linked to Anonymous, @YourAnonOne, that it had Vladimir Putin's regime in its sights.
The Anonymous collective is officially in cyber war against the Russian government. #Anonymous #Ukraine
— Anonymous (@YourAnonOne) February 24, 2022
In the days since, the group has claimed credit for several cyber incidents including distributed denial of service attacks – where a site is rendered unreachable by being bombarded with traffic – that have brought down government websites and that of Russia Today, the state-backed news service. The DDoS attacks still appeared to be working on Sunday afternoon, with the official sites for the Kremlin and Ministry of Defence still inaccessible.
Anonymous also said it had hacked the Ministry of Defence database, while on Sunday it was claimed the group had hacked Russian state TV channels, posting pro-Ukraine content including patriotic songs and images from the invasion.
JUST IN: #Russian state TV channels have been hacked by #Anonymous to broadcast the truth about what happens in #Ukraine. #OpRussia #OpKremlin #FckPutin #StandWithUkriane pic.twitter.com/vBq8pQnjPc
— Anonymous TV 🇺🇦 (@YourAnonTV) February 26, 2022