These nations export technical know how to pretty much anyone with the funds, not unlike any of the 60’s TV bad guys that Hollywood was so fond of creating.
The Belgian contractor sold the U.S. the plans for Saddam’s bunker complex in Baghdad. Somebody (probably MOSSAD, possibly the CIA) inserted stuxnet into Siemens centrifuge software. Bribing a German software engineer to sabotage Iranian software isn’t that hard.