Often, the most critical threats come from within an organization itself. This is true for all sectors, but it is especially true for industrial control systems (ICS). Technicians in these environments already have access to plant controls and may have the deep knowledge of industrial processes needed to achieve specific goals. The damage caused by an insider may range from mild disruption to major disaster depending on what is attacked.
A Story of a Disgruntled Insider
This was the case in March 2000 when officials in Maroochy Shire (Queensland, Australia) discovered malfunctioning pumps and alarms within their new wastewater system. The engineering firm contracted for the installation confirmed that someone was attacking the plant using RF signals, so the plant hired private detectives to investigate.