Worm
Stuxnet
aka W32.Stuxnet
A landmark cyber-physical weapon that sabotaged Iran's uranium enrichment centrifuges by targeting Siemens PLCs, first uncovered in 2010.
Stuxnet was the first widely documented piece of malware engineered to cause physical destruction. Discovered in 2010, it targeted Siemens S7 PLCs controlling centrifuges at Iran's Natanz enrichment facility, subtly varying their speed to damage them while feeding operators normal readings.
Engineering
Stuxnet was extraordinary in sophistication: four Windows zero-days, drivers signed with stolen legitimate certificates, a PLC rootkit, and the ability to cross air gaps via infected USB drives. It checked for very specific hardware configurations and lay dormant elsewhere.
Legacy
Stuxnet is widely reported to be the "Olympic Games" operation by the US and Israel. It redefined cyber conflict and inspired a generation of ICS/OT research. The PLC payload teardown lives on the Reverse Engineering Hub; the operation is profiled on Cyber Breaches.
Defense
Air-gap discipline, removable-media controls, and OT/ICS monitoring for anomalous controller behaviour.