Internet Advertising company DoubleClick had some downtimes today because of a massive Denial-of-Service attack. The DoS attack started at about 10.30 am EDT in the U.S. and the attack considerable slowed down the companies website and advertising servers, which distribute advertisements to other websites on the internet.
Ripple effects from the attack were felt across the internet as webpages with DoubleClick ads had problems retrieving the ads from DoubleClick, causing "severe disruption" for DoubleClick's customers.
Leading Web sites all experienced significant slowdowns during the period covered by the attack, including Web pages for the Washington Post Co., New York Times Co., Cnet Networks Inc., Nortel Networks Corp. and InfoWorld magazine, according to Keynote Systems Inc., a Web performance measurement company in San Mateo, Calif.
Keynote measurements for the period covered by the attacks show that the "base page" -- or basic HTML documents -- served by those Web sites loaded quickly, but that the "full page," which includes any content the Web page points to, suddenly began to load very slowly, said Lloyd Taylor, vice president of operations at Keynote.
DoubleClick's DNS servers were the target of the attack, which came from unidentified "outside sources" and lasted for approximately four hours, said Jennifer Blum, vice president of corporate communications at DoubleClick.
Keynote recorded a threefold slowdown in response time for Web pages beginning at about 7 a.m. EDT and ending at 1:30 p.m. EDT. The company doesn't know what caused the slowdowns, but the behavior of the pages is consistent with a DoS attack, Taylor said.
The performance of DoubleClick's servers had returned to normal by late this afternoon, Taylor said.
Staff members are taking steps to "resolve the situation permanently," Blum said.