Israel Tested Stuxnet Worm Before Iran Attack Tests on centrifuges in Israel helped make worm to effective By Mark Russell, Newser Staff Posted Jan 16, 2011 9:14 AM CST 10 comments Comments The Stuxnet worm that crippled Iran's nuclear weapons program was tested in Israel by a joint US-Israeli program, reports the New York Times. (AP Photo/IIPA,Ebrahim Norouzi) (Newser) – The high-tech computer virus that derailed Iran's nuclear program last year was tested in Israel as part of a joint US-Israel program, reports the New York Times. Israel's Dimona complex, home to its hush-hush nuclear arms program, tested the Stuxnet worm on nuclear centrifuges nearly identical to the ones Iran uses. “To check out the worm, you have to know the machines,” says an American expert on nuclear intelligence. “The reason the worm has been effective is that the Israelis tried it out.” The US and Israel deny all involvement. Stuxnet apparently destroyed about one-fifth of Iran's centrifuges last year, leading US and Israeli officials to conclude it will now be at least 2015 until Iran can bring a nuclear weapon online. And there could be more to come: The Stuxnet worm, called incredibly complex and ingenious by experts who have seen the code, has the seeds to spawn more versions of itself and more attacks.