Theories about who actually created it abound, and the one that says the US and Israeli government were behind it has been voiced more often than others.
If a report by Industrial Safety and Security Source is to believed, current and former US intelligence sources have confirmed that Israel's intelligence agency Mossad is responsible for the worm's introduction into the plant's systems.
The worm is believed to have been placed on a specially crafted USB memory stick and handed over to a Natanz worker who, by all accounts, was an Iranian national belonging to a dissident group named Mujahideen-e Khalq (MEK).
The MEK is considered to be Mossad's assassination arm, and besides being responsible for the Stuxnet infection, they are also supposedly the ones behind the large number of murders of Iranian nuclear scientists and a few bombings.
According to US sources, both the US and Israel have been involved in the creation of Stuxnet, but the US is not involved in the aforementioned killings.
The incident with Stuxnet is not the first time that the US intelligence community used a virus to spy on and disable the systems of opponents.
In the 1980s they targeted Soviet military and industrial structures, and in 1991, just before Desert Storm, the CIA and the British GCHQ injected malware into Iraqi computers.