Cyber Security company Palo Alto came to the conclusion linking the attackers to the SolarWinds operation that saw Russian agents gain access to at least nine US government agencies in 2020. The success of that spying operation - which was only detected when the hackers also decided to steal tools from US cyber security company Mandiant - prompted a significant response from US authorities. It led to the US announcing new sanctions on Russia and its officials, although Russian government spokespeople repeatedly denied being to blame. At the time Microsoft president Brad Smith called the supply-chain attack "the largest and most sophisticated attack the world has ever seen" although some commentators criticised this description. READ MORE: Ukraine horror: Russian hackers 'gain access' to war documents