An article and white-paper (To Kill a Centrifuge) set the record straight and correct some misconceptions about Stuxnet. Ralph Langner spent years studying the particularities of the nuclear plant at Natanz. An earlier version, with a totally different infection vector and payload almost went undiscovered, if it wasnt for a sample found on the multiple antivirus engines scanner VirusTotal, showing it had been active since at least 2007. According to Langner, the capability was there to cause massive damage all in one go but instead the attacker took great care not to go for it, at least not in such a way.”]
Source: https://blog.malwarebytes.com/threat-analysis/2013/11/stuxnet-new-light-through-old-windows/