Report: DDoS Attacks Still Growing, But At Slower Rate

The number of distributed denial-of-service (DDoS) attacks grew 20 percent last year -- a major decrease in the rate of attacks from 2007 to 2008, when these debilitating attacks increased 67 percent, according to a new report.

Arbor Networks, which today released its annual worldwide security infrastructure report using data gathered from more than 65 IP network operators across the Americas, Europe, Africa, and Asia, found the largest attack was 49 gigabits-per-second from third quarter 2008 through third quarter 2009.

"Last year, we saw a doubling in the sheer volume of these attacks and 40-Gbps was the major finding. To my surprise, only 20 percent" more of these attacks occurred in the past year, says Craig Labovitz, chief scientist for Arbor. The largest sustained DDoS attacks were 40 Gbps and 24 Gbps, he says.

So why the dramatic drop in growth and capacity of DDoS attacks? "There are two things going on. First, diminishing returns: Once you're in the 40-gigabit range, that's more than enough bandwidth to take out data centers," Labovitz says. "Attacks that large become counterproductive. You are at the saturation point."

And data centers today are also more distributed and replicated, he says. "They are no longer quite as susceptible to brute-force volume attacks," Labovitz says.

Even so, DDoS attacks are basically a routine occurrence for service providers and large enterprises these days, he says. "A majority of attacks become part of the business for service providers and enterprises. There are new procedures and equipment in place at most providers so they can deal with 1 to 2-gigabit DDoS attacks...Pure bandwidth attacks can be addressed by most providers."

Meanwhile, attackers are employing more smaller-scale DDoS attacks that are harder to detect, yet just as lethal. "Lower-bandwidth attacks can be equally as disruptive to e-commerce and gambling sites, [for example], and more difficult to mitigate," Labovitz says.

In the report, 35 percent of the respondents said they expect attacks to move to the cloud, with more sophisticated service and application attacks to be their biggest operational threat during the next 12 months. More than 21 percent expected large-scale botnet-based attacks to be the biggest threat.

The report also pinpoints the "perfect storm" of issues network operators are facing that could also increase security threats, including the move to IPv6, DNSSEC, and to 4-byte ASNs. "The concern is that when you start making any infrastructure changes to router software or operations, there are associated security and availability concerns," Labovitz says. "Any new technology has an exposed security surface [trade-off]," he says.

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