Cyber-attacks have become a big deal in the mainstream news recently. Several major Web sites fell victim to denial of service attacks in July and August (read more about denial of service attacks in “Zombie Attack“). Twitter was the most notable to get victimized, as hackers twice brought the social networking site to its knees for several days. Media reports suggested Russian operatives staged at least one of the attacks to silence a blogger critical of Russia’s policies toward the nation of Georgia.

However, cyber-attacks threaten not only businesses, but also critical infrastructure. With more and more of American society reliant on the Internet, terrorists could theoretically bring down important parts of the nation’s infrastructure–hospitals, utilities, communication channels such as Twitter or government agencies, for example–through Web-based attacks.

“[These] attacks are not necessarily meant to get at customer data but are just meant to shut down systems and wreak havoc,” says Susan Lyon, of counsel at Perkins Coie.

She mentions that systems such as hospitals, phone lines, electricity and even Twitter are crucial during a national disaster or security crisis. But as the Twitter hackers showed in August, these systems are also vulnerable to attack.

President Obama supports development of a national cybersecurity policy. At press time, he was expected to soon announce a national cybersecurity adviser, although he ran into a significant hitch when the main contender for the job, Melissa Hathaway, cybercoordination executive for the Office of the Director of National Intelligence, announced her resignation Aug. 4.

Although some experts applaud Obama’s concern for online national security, privacy advocates are wary of government invasion of personal privacy, and corporate leaders fear too much government intervention into their businesses.