Starting out as a loose online community of hackers and cyber-pranksters, Anonymous quickly rose to fame through collaborative “hacktivism” by targeting entities including The United States, Israel, Tunisia, Uganda, the Islamic State, child pornography sites, copyright protection agencies, and cults; in addition to corporations such as PayPal, MasterCard, Visa, and Sony. Anonymous is identified by their masks inspired by the graphic novel “V for Vendetta”, and are known for their motto: “We are Anonymous. We are legion. We do not forgive. We do not forget. Expect us”. Many people view them as, “freedom fighters” and “digital Robin Hoods”, while governments see them as “cyber terrorists.” In February 2022, Anonymous ‘declared war’ against Russia, vowing to disrupt the country’s internet access and critical IT infrastructure in retaliation against Putin’s actions in the Ukraine. Since this tweet, Anonymous has claimed responsibility for over 100 cyber attacks against Russia, including breaching the Russian CIS Center (that coordinates information and regulatory practices on trade, finance, lawmaking, and security between CIS Member States) and deleting data, renaming files to things like “putin stop this war”, “stop war”, “no war”, “HackedByUkraine”, and extracting a number of secret keys. Additionally, Anonymous has disrupted the websites of Oil Giant Gazprom (oil giant), state-sponsored new channel Russia Today, and shut down the Control Center of the Russian Space Agency. Anonymous also claims to have hacked Russian state TV stations Russia 24, Channel One, and Moscow 24 in order to air footage of the war in the Ukraine, which many Russians weren’t even aware of due to state censorship.

References
https://auralcrave.com/en/2022/03/02/anonymous-who-are-they-and-what-are-their-most-famous-hacks/ 
https://www.websiteplanet.com/blog/cyberwarfare-ukraine-anonymous/ 
https://www.cnbc.com/2022/03/16/what-has-anonymous-done-to-russia-here-are-the-results-.html