Predating Stuxnet: How the “fast16” Malware Secretly Sabotaged Nuclear Weapons Simulations

Symantec Threat Hunter researchers report discovery of "fast16", a sophisticated, state-level malware framework (dating back to ~2005) that installs a kernel file-system filter and uses 101 targeted byte-pattern hooks to inject code (including a Lua VM) into LS-DYNA and AUTODYN simulation processes; it then applies surgical algorithmic manipulations (Mechanisms A–C) — for example reducing Cauchy stress tensor outputs to 1% when material density reaches 30 g/cm³ — to covertly corrupt uranium-compression and high-explosive simulations, effectively sabotaging nuclear weapon design efforts without crashing the host applications.