Process safety and the Stuxnet worm

A news article mentions the following: "A sophisticated worm designed to steal industrial secrets and disrupt operations has infected at least 14 plants, according to Siemens.Called Stuxnet, the worm was discovered in July when researchers at VirusBlokAda found it on computers in Iran. It is one of the most sophisticated and unusual pieces of malicious software ever created -- the worm leveraged a previously unknown Windows vulnerability (now patched) that allowed it to spread from computer to computer, typically via USB sticks.
The worm, designed to attack Siemens industrial control systems, has not spread widely. However, it has affected a number of Siemens plants, according to company spokesman Simon Wieland. "We detected the virus in the SCADA [supervisory control and data acquisition] systems of 14 plants in operation but without any malfunction of process and production and without any damage," he said in an e-mail message".
As technologies become more and more complicated, chemical plants are also becoming susceptible to attack through the software and other technologies they use. Do not be complacent about your plant software security systems. Many chemical companies ban USB sticks inside their premises.
Read more of the article in this link.