Akamai Technologies Inc. said a "sophisticated, large-scale distributed denial of service attack" on its domain name service bogged down several of its clients' Web sites yesterday morning, and that it's investigating the incident with federal authorities.
"The problem was quickly detected by Akamai's automated monitoring systems," said Jeff Young, a spokesman for the Cambridge, Mass.-based company, which distributes the content of major Web sites on its servers across the globe. "Akamai personnel mitigated the attack by working closely with customers, making key adjustments in the company's infrastructure and cooperating with several network partners around the world to shut down the source of the attack."
He added that only 4% of the company's 1,100-plus customers were affected, that only 2% saw a noticeable impact and less than 1% suffered significant problems affecting more than 20% of their users.
The attack caused delays and some timed out domain name service requests, and some Internet users trying to reach affected sites got slow responses from the server, Young said, adding that contrary to media reports, there was no outage of services.
"Akamai continued to serve both DNS requests and Web site content for customers throughout the period of the attack," he said. All problems were resolved after a couple of hours.
Lenny Zeltser monitors Web activity for the Internet Storm Center, a service of the SANS Institute of Bethesda, Md. He said the storm center started to receive numerous reports of a widespread Akamai outage around 8:30 a.m.
Affected sites were Yahoo, Google, Microsoft, FedEx, Xerox, Apple and likely many others, Zeltser said. The situation improved around 10:30 a.m., mainly because some of the affected domains temporarily switched from using Akamai DNS servers to their own servers, he added.
Zeltser said it appears only Akamai customers were affected by the attack.
"We do not currently know of any sites that were affected by the attack without using Akamai's services," he said.