"A new report [...] claims that the Stuxnet worm that crippled Iran’s nuclear program at the Natanz facility was planted by an Israeli “proxy”, essentially an Iranian that was working for Israel. "

From http://www.techspot.com/news/48184-israeli-double-agent-planted-stuxnet-work-using-a-memory-stick.html , FYI,
David
Israeli double agent planted Stuxnet work using a memory stick
By Shawn Knight
On April 13, 2012, 4:30 PM EST
Comments 15
stuxnet, worm, israe
A new report from Richard Sale of ISSSource claims that the Stuxnet worm that crippled Iran’s nuclear program at the Natanz facility was planted by an Israeli “proxy”, essentially an Iranian that was working for Israel. The report further indicates that similar proxies have been used to assassinate scientists enlisted to help Iran build a nuclear program, although officials have said that the US never indulged in targeted killings.
The proxy was able to load the worm onto a memory stick and directly upload it to a system on the network. Once activated, it infiltrated the entire network and took over the necessary systems. The revealing information comes from current and former US intelligence officials who have asked to remain anonymous due to their proximity to ongoing investigations, according to the report.
If you are unfamiliar, Stuxnet was a computer worm created jointly by the United States and Israel designed to infiltrate and disrupt Iran’s nuclear program. The worm has been regarded as the most sophisticated every developed as it used 20 zero-day security exploits. It remained untraceable by all anti-virus software as well. It took security researchers several months to deconstruct, analyze and fully understand its purpose.
When the time was right, Stuxnet deployed its payload which only targeted Siemens supervisory control and data acquisition (SCADA) systems and other select systems. The goal of the attack was to damage the centrifuges used to enrich uranium for nuclear use.