The U.S. is again prosecuting a Korean-American, Juwhan Yun, who earlier served 30 months in prison for offering to export 500 bombs full of nerve gas. Yun didn't have the 500 pound bombs, or the nerve gas, but he had entered into negotiations with Iranian officials, who were very interested. Iran has nerve gas, but very low quality stuff, and were eager to obtain higher grade sarin gas.
Yun behaved himself after he got out of jail in 1991, but was arrested again on April 15th, and is now accused of negotiating with South Koreans to obtain Russian RD-180 rocket engine technology for them. This would enable South Korea to get into the satellite launching business. It's unclear if Yun actually had access to this technology. The investigation, which involved obtaining thousands of Yun's emails and telephone conversations, revealed that Yun was also peddling other high tech items (radar, sensor and smart bomb technology.) Yun claimed to be working with South Koreans who were trying to steal rocket technology from Western nations as well.
There has been some technology stealing activity in South Korea, but nothing compared to the Iranian efforts. For the last three decades, Iran has had to deal with embargoes that prevent it from getting spare parts for its large inventory of elderly Western weapons. In response to this, Iran has sought to obtain spare parts via a smuggling network, with some of the less complex parts manufactured inside Iran. The network is under increasing assault, as the U.S., and other Western nations uncover parts of the network, and prosecute those running it. Yun is not the only person to plug into this network, and try to scam the Iranians. Some of these criminals have succeeded in deceiving the Iranians, who simply swallow these losses and write them off as a cost of doing business.