to counter the new Duqu worm that was first discovered 2-1/2 months ago. Duqu is quite different from the famed Stuxnet worm. Stuxnet was designed to disrupt centrifuge operations at only one site, the Natanz centrifuge plant. Duqu is designed to spy on industrial plants all over the world and sent back information on their operations. Duqu counters have been on the market for several weeks. Iran did not say how its counter differed from the others.