Although AboveNet restored service by midafternoon, many of its 1,000 dot-com customers experienced sluggish Web site performance--or total outages in some cases--since midmorning, according to Paul Vixie, senior vice president of Internet services for Metromedia Fiber Network, AboveNet's parent company.
"Almost all of (our customers) felt some kind of pain from this," Vixie said. "This was a malicious and painful attack."
AboveNet, which hosts Web sites for AOL.com, Quotesmith.com and many others, hasn't yet determined the extent of the impact of the attack on the company's revenue. Executives declined to offer more specifics about how the attack was engineered, citing the pending federal investigation.
Executives said the FBI and the National Infrastructure Protection Center, a government-backed computer crime investigation organization, are investigating the attack.
The AboveNet attack marks one of the first significant incidents of alleged cybervandalism since the Internet industry was gripped by several days of attacker-initiated outages that knocked out service at several major Web sites in February.
In that case, attackers used a networking trick known as a "denial of service attack" to flood certain Web servers with information requests, effectively swamping those computers and shutting them down. Canadian police this month arrested a 15-year-old in connection with those outages.
Although the results of today's attack were similar, AboveNet executives were quick to characterize the nature and method of this attack as different. "This was not a classic denial of service attack," Vixie said. "It wasn't anything like the flooding attacks of a couple months ago."