ABC News 
October 19, 2011
A new computer virus using “nearly identical” parts of the cyber superweapon Stuxnet has been detected on computer systems in Europe and is believed to be a precursor to a new Stuxnet-like attack, a major U.S.-based cyber security company said today.
Stuxnet was a highly sophisticated computer worm that was discovered last year and was thought to have successfully targeted and disrupted systems  at a nuclear enrichment plant in Iran. At the time, U.S. officials said the worm’s unprecedented complexity and potential ability tophysically sabotage industrial control systems  — which run everything from water plants to the power grid in the U.S. and in many countries around the world — marked a new era in cyber warfare .
Though no group claimed responsibility for the Stuxnet worm, several cyber security experts have said it is likely a nation-state created it and that the U.S. and Israel were on a short list of possible culprits.
Whoever it was, the same group may be at it again, researchers said, as the authors of the new virus apparently had access to original Stuxnet code that was never made public.