Stuxnet Virus   

Stuxnet is a malicious computer worm. Stuxnet specifically targets programmable logic controllers (PLCs), which allow the automation of electro mechanical processes such as those used to control machinery on factory assembly lines, amusement rides, or centrifuges for separating nuclear material. Exploiting four zero-day flaws. Stuxnet functions by targeting machines using the Microsoft Windows operating system and networks, then seeking out Siemens Step7 software. Stuxnet reportedly compromised Iranian PLCs, collecting information on industrial systems and causing the fast-spinning centrifuges to tear themselves apart. Stuxnet’s design and architecture are not domain-specific and it could be tailored as a platform for attacking modern supervisory control and data acquisition  and systems (e.g., in factory assembly lines or power plants), the majority of which reside in Europe, Japan and the US. Stux net reportedly ruined almost one fifth of Iran's nuclear centrifuges.

                                           

                                                                   

Source...https://en.wikipedia.org/wiki/Stuxnet