Could your TV attack? National security officials say cyberspies from Russia, China, and other countries have penetrated the U.S. electrical grid and are preparing to wreak havoc. Intelligence officials worry the attackers could hijack electrical facilities, nuclear power plants, or financial networks if they choose; water and sewage systems are also at risk. Russia and China have denied any involvement in the hacking, and it is almost impossible to know if the cyberspies are government-sponsored. A little hacking can go a long way: In 2000, an angry employee rigged a water-treatment plant in Australia to release more than 200,000 gallons of sewage into parks and other public places.