The report that the Chinese government staged a massive cyberattack upon Ukrainian infrastructure in the days leading to the 24 February 2022 Russian invasion should be met with mild skepticism: the apparent source is Ukrainian intelligence, which has its own imperatives. Still, it is entirely plausible, and we should view it within the larger context, because that context ought to shape our understanding of events now.
China is not an aggressor in the Ukraine war — not exactly — but it is the sole meaningful ally to the aggressor, which is the Russian state. (We may dispense with Belarus, Syria, et al., here: the qualifier is meaningful.) We can be reasonably sure that the People’s Republic at minimum had advance notice of the invasion, given the Xi-Putin visit and “no limits” statement of alliance at the opening of the Beijing Winter Olympics, and the invasion’s timing deftly avoiding the Games’s public narrative. The PRC, of course, also had advance warning of the invasion from the Americans — and they promptly shared our intelligence with the Russians. We are reasonably sure that Russia requested military aid — though not troops — from Beijing for use in Ukraine, a couple weeks in to the war, and that Beijing at minimum did not reject the inquiry out of hand. Finally, on the material front, China has acted as a prop for the sanctions-stricken Russian economy, providing an alternative source of imports and an emergency source of finance as European and American trade abruptly evaporated.