White House officials are still unsure who is responsible for a denial-of-service (DoS) attack Friday on the U.S. presidential Web site http://www.whitehouse.gov.
The attack caused "some degradation" of service beginning at about 8:00 a.m. Eastern time, and blocked access entirely between about 9:00 a.m. and 11:15 a.m., spokesman Jimmy Orr said Monday.
Technical staff are taking measures to beef up security at the White House servers, he said.
It's not the first time hackers have targeted the U.S. president's Web site, Orr said. "It has happened during the past administration that the Web site was down for a day or two a few times."
Asked whether investigators suspect a link between the incident and a series of recent attacks on U.S. government servers attributed to Chinese hackers, Orr would only say, "I can't speculate at this time."
The U.S. National Infrastructure Protection Center (NIPC), the office of the U.S. Federal Bureau of Investigation (FBI) responsible for computer security, warned late last month of an upswing in attacks against U.S. servers by Chinese hackers, given an increase in political tensions between the countries. A spokeswoman for NIPC could not be immediately reached for comment Monday.