The infamous worm infected systems at Iran's uranium enrichment facility at Natanz in 2009 and 2010, hobbling high-speed centrifuges after infecting computers connected to SCADA industrial control systems at the plant.
The sophisticated attack, seen as an alternative to a military strike against the facility, is credited with putting Iran's nuclear programme back by between 18 months to two years. The malware worked by infiltrating the SCADA systems used to run the high-speed gas centrifuges. It then randomly, and surreptitiously, speeded them up and slowed them down to induce seemingly random, but frequent, failures.
However, a journal article published by the Royal United Services Institute (RUSI) claims that Iranian authorities redoubled their efforts after Stuxnet was discovered, so that production of fissile material went up - rather than down - a year after the SCADA-busting worm was discovered.
The malware acted as a wake-up call that prompted the Iranians to throw more resources at the nuclear project, bonded personnel together and prompted security audits that uncovered vulnerabilities that might otherwise have gone unnoticed...
