What if our financial, energy, water, defense, telecommunications, and other systems were invaded by botnets? Sure we have backup systems in most cases, but wouldn't the attackers also attack those? There are some naysayers who think that most terrorists won't waste their time on cyber attacks and prefer attacks directly against humans. It may be true, but is the risk of not securing our technology worth it? Who is to say that only terrorists would engage in these attacks. How about criminals or other other enemies?
Think of such an attack that is timed to happen as a physical attack takes place or is timed to occur during a natural disaster. I think you see where I'm going. A cyber attack in itself might not cause much damage, but add other factors, and the damage cascades.
As politicians and the military start to think about these problems, they turn to outside security experts. One, who has advised the US military and the US government, is Sami Saydjari, head of a consultancy called the Cyber Defence Agency. His view is that America's enemies will use cyberspace to create havoc in the physical world by attacking critical infrastructure with botnets.
He ran a scenario called Dark Angel that involved simultaneous cyber attacks on the power grid, banking, telecommunications and oil and gas supply. "Think of the damage Hurricane Katrina wrought, where a portion of our country became a Third World country. And if you imagine that level of damage a thousand-fold, you will understand the level of damage we are forecasting." [BBC]