Well, it finally happened: A worm has been developed that can break into computers which control machinery at the heart of industry. Such a security breach could allow attackers to assume control of critical systems like pumps, motors, alarms and valves in an industrial plant. Worse, safety systems could be switched off at a nuclear power plant; fresh water contaminated with effluent at a sewage treatment plant, or the valves in an oil pipeline opened, contaminating the land or sea.

The worm is called Stuxnet and it's about 600-kilobytes in size. It was professionally written, an indication that a nation-state or organized crime outfit is likely behind it.

This worm will prove particularly problematic for legacy systems, but it's also a wake-up call for new distributed systems such as smart grids. Security will have to be embedded in the architecture right from the start to avoid such vulnerabilities.

Source.