There has always been speculation that something like this could happen, it’s probably just an idle threat but it could be serious
If you are Russia and tired of all the NATO weapons being shipped to Ukraine, why not unleash hackers inside of Russia and elsewhere on the Western banking system, if it works it could be devastating and you would have plausible deniability
These hackers could be anywhere not necessarily inside Russia
Well, it would not take much to cause distrust in banking and a massive run on the bank.
To bad most people do not understand that there is no where near enough M1 money supply to cover all deposits.
Welcome to the money multiplier and the Federal Reserve Act of 1913.
There is lots of US money in private hands in Russia. It used to be used as a bulwark against Rubble devaluation, that is until Biden began to go the way of the German Weimar Republic printing money as fast as they could.