// Image depicting flow of virus in layman terms Iran Nuclear Tests 2010 Natanz nuclear facility, Iran SCADA systems were infected with Stuxnet named virus in 2010. Size of virus: 500 KB. Entered through: Infected USB Stick of one of the employee. Working: It simply controlled the PLC and opened the backdoor for attackers. Victims: Over 15 nuclear facilities were infected, while source being Natanz nuclear facility.