The Sanctions have probably done the Iranian,and Russian banks, a Favour,as some if not all of their Banks have been cut off from the (SWIFT),.Money Transfer.System,..so their Banks I would say are relatively safe for now,..secondly they mainly use their own currencies the rial & the ruble when trading between their 2 countries

The Sanctions are probably what saved the Russian banks, as most have been cut off from the SWIFT,.Monetary Transfer.System,..,.