Attack Size Still on the Rise, But at a Slower Pace

In previous versions of the Worldwide Infrastructure Security Report, service providers reported near doubling in peak distributed denial of service (DDoS) attack rates year-over-year, with peak attack rates growing from 400 Mbps to more than 40 Gbps since 2001. This year, providers reported a peak sustained attack rate of 49 Gbps, a 22% growth over last year's peak of a 40 Gbps attack, which shows the attack scale growth has slowed in the past 12 months. As comparison, last year's 40 Gbps attack represented a 67% increase over the largest attack reported in the 2007 survey.
Additionally, only 19% of survey respondents reported the largest attacks they observed as being within the one-to-four Gbps range this year, as opposed to some 30% in 2008.