Stuxnet was Sabotaging Iran’s Nuclear Plant a Year Earlier than Assumed

According to researchers, the Stuxnet worm was officially authorized by former President George W. Bush in Jan 2009 to sabotage Iran's nuclear program. The previous version of the worm, Stuxnet 0.5, was at work since Nov 2007 and halted in July 4, 2009.

Bush, the former President approved the use of covert activities in Jan 2009 to inhibit Iran from developing nuclear plants using uranium works at Natanz, a year before he left the office.

This version of worm is used to disrupt machinery that enhances uranium. The worms find Siemens programmable logic controllers to close the valves at the right time that fed a gaseous state of uranium ore into centrifuges for separating out the uranium. By closing at the right time the valves disrupt the flow of the gas and thereby, damage the centrifuges.

Firstly, the normal system state of machinery is analyzed by the worm so as not to allow negative effects of the damage take place. "It will also prevent modification to the valve states in case the operator tries to change any settings during the course of an attack cycle", the blog post says.

Moreover, the blog post says that Stuxnet carefully analyzed the potential target Siemens machines to ensure they were in the Natanz facility.