But in large corporate computer systems, these patches can have an impact on other internal systems.

CNN: Sasser worm rips through Internet

Jan Verplancke, the chief information officer of Standard Chartered, says that international banks build their large computer systems in the places that have the most reliable communications and power networks and are least prone to natural disasters.

ECONOMIST: Winners and losers

Perfect Citizen will look at large, typically older computer control systems that were often designed without Internet connectivity or security in mind.

WSJ: U.S. Program to Detect Cyber Attacks on Infrastructure