Started in Germany, the stuxnet has infected over 45,000 industrial control system in India, Pakistan, Indonesia, Canada,United State Of America and recently (25 Sept 2010) Iran. The worm can cause many malfunction in factory electrical system.
A previous historic example includes a reported case of stolen code that impacted a pipeline. Code was secretly “Trojanized” to function properly and only some time after installation instruct the host system to increase the pipeline's pressure beyond its capacity. This resulted in a three kiloton explosion, about 1/5 the size of the Hiroshima bomb.
