Stuxnet, one of the most sophisticated pieces of malware ever written, was discovered in 2010. This complex malware took many months to analyze and the eventual payload significantly raised the bar in terms of cyber threat capability.
Experts believe that Stuxnet damaged or destroyed centrifuges at Iran's Natanz plant in about 2009. The cyber attacks were attributed by security experts to U.S. and Israeli intelligence. Stuxnet proved that malicious programs executing in the cyber world could successfully impact critical national infrastructure.
Previously, the earliest known variant of Stuxnet was version 1.001 created in 2009.