A U.S. court recently convicted a naturalized American citizen, Mohammad Reza Vaghari, of buying electronic equipment and illegally exporting it to Iran (via an associate in Dubai). Vaghari, who became a citizen in 2005 (and lied on his application for that as well), could receive up to eight years in prison. These prosecutions are becoming more common, not just in the United States, but in many other Western nations where Iran conducts its smuggling operations.
For example, last year, for the first time, Canada prosecuted one of its citizens, Mahmoud Yadegari, for trying to smuggle nuclear research equipment to Iran. While Iranian born, Yadegari is a Canadian citizen, and had bought ten pressure transducers (needed to enrich uranium for nuclear warheads) from an American firm, stating he was shipping them to Dubai (and then smuggled from there into Iran). Yadegari was detected, arrested, convicted and sentenced to 51 months in jail. He also lost his house, and his wife fled back to Iran with their child.
Many Western nations, in addition to the United States, have become more aggressive in going after Iranian technology and hardware smuggling. Australia recently stopped a shipment of pumps that, it turned out, were capable of being used in nuclear power plants (as well as for more benign uses). Iran has been quite blatant about buying dual use equipment, and then openly using the stuff for military purposes. That bravado is backfiring.
Ever since the U.S. embargo was imposed in 1979 (after Iran broke diplomatic protocol by seizing the American embassy), Iran has sought, with some success, to offer big money to smugglers who can beat the embargo and get needed industrial and military equipment. This is a risky business, and American and European prisons are full of Iranians, and other nationals, who tried, and often failed, to procure forbidden goods. The smuggling operations are currently under more scrutiny, and attack, because of Iran's growing nuclear weapons program. But the Iranians simply offer more money, and more smugglers step up to keep the goodies coming.
The U.S. has gotten more aggressive, and successful, at shutting down Iranian smuggling operations. Not just by bribing the smugglers themselves, but also by getting the cooperation of nations the smugglers operate out of. This has been so successful that most of these smugglers no longer feel safe working out of Arab Persian Gulf nations (especially the United Arab Emirates). As a result, more smugglers are operating out of Malaysia, and the U.S. is trying to shut down that activity. America also monitors the international banking network, seeking signs of smuggler activity, and leaning on the banks involved, to step back.
The smuggling effort has been a mixed success. The Iranian armed forces are poorly equipped, because new tanks, warplanes and ships could not be sneaked in. Thus major weapons acquired in the 1970s are falling apart for want of sufficient replacement parts.