The Guardian is reporting that the Stuxnet malware worm could well be a strategic attack on Iran's infrastructure by another national government agency, with Israel mentioned as the possible suspect.

The malware, which has been described as one of the "most refined pieces of malware ever discovered", could have taken a team of five to ten top hackers 6 months to cook up.

Security specialist Symantec has stated that six out of every ten computers infected with the worm are found in Iran, and that it was said to be targeting computer terminals at places such as nuclear plants, rather than banks - leading to suggestions that the aim was to bring down Iran's substructures.

Graham Cluley, senior consultant with the online security company Sophos, said: "There is circumstantial evidence to suggest Iran was the target of Stuxnet. We know the worm was designed with a specific target in mind - its makeup and the way it executes render the telltale signs.

"Combine this with the fact that the worm was identified by a Belarussian security firm working for an Iranian client and the fact that the nuclear power plant was not working properly for months, it is understandable that speculation points towards Iran as the target".

When Stuxnet is loaded onto a PC it exploits Windows security holes and controls a Siemens component, called Simatic WinCC, which is used in factory operations.

Alan Bentley, senior international vice president at Lumension, said: "It was aimed right at the heart of a critical infrastructure".