Report: Stuxnet targeted five separate sites in Iran

The report, released Friday by Symantec, a computer security software firm, said there were three waves of attacks. Liam O Murchu, a security researcher at the firm, said his team was able to chart the path of the infection because of an unusual feature of the malware: Stuxnet recorded information on the location and type of each computer it infected…

At least three and possibly four versions of the program were probably written, and the researchers discovered that the first version had been completed just 12 hours before the first successful infection in June 2009. The researchers speculated that the first step in the infection was either an infected e-mail sent to an intended victim or a hand-carried USB device that carried the attack code.