An attack on hundreds of web sites in South Korea earlier this week continues to clog websites in the United States.
Officials say cyber attacks have affected U.S. government Web sites including those of the White House, departments of Homeland Security, Defense and Treasury and the Voice of America.
The attackers do not appear to be interested in breaking into computers to steal information but to give the impression that something is wrong with the entire system.
"These attacks are causing targeted websites to slow to a crawl or even stop working altogether," says Jayson Street, an informational warfare specialist for the website Netragard.com in Oklahoma City, Oklahoma.
South Korean officials suspect the attacks originated in North Korea but they have been unable to confirm their suspicions. Finding out who is behind these attacks may be impossible.
The masterminds of these attacks spread a virus from one personal computer to another which directs data traffic to the targeted Web sites.
"When 30,000 or 40,000 computers ask for the same information at the same time, this becomes a real mess," says Street. Even if an investigation finds the owners of some of those personal computers it could takes years to find the computer that originated the cyber mischief.