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Average Peak Size of DDoS Attacks Spiked in Q2: VeriSign

The average peak size of distributed denial-of-service (DDoS) attacks in the second quarter of 2014 increased by 216% compared to the first quarter, according to the latest trends report from VeriSign.

The report shows a year-on-year increase of 291% in average peak attack size, with 65% of the cyberattacks monitored by the company exceeding 1 Gbps. This is worrying news, especially for small and medium size businesses that usually have less than 1 Gbps of upstream bandwidth. Between April 1 and June 30, attacks in the 5-10 Gbps range increased by 33%, while ones greater than 10 Gbps increased by 16% compared to the first three months of 2014.

The media and entertainment industry has been the most targeted (43%), followed closely by the IT services/SaaS/cloud sector (41%). The financial and the public sectors each accounted for only 5% of attacks, the company noted.

Recent reports informed of a decrease in the number of Network Time Protocol (NTP) servers that could be abused for DDoS attacks, and a slight drop in NTP amplification attack traffic. However, VeriSign says the primary attack vector for UDP floods continues to be large NTP floods.

"VeriSign observed increasing complexity in second-quarter DDoS attacks, including attacks that quickly and unpredictably changed vectors over the course of the mitigation," the report reads. "VeriSign saw sophisticated TCP and UDP floods that targeted specific customer application ports and continuously switched vectors."

One of the sophisticated attacks mitigated by VeriSign in the second quarter was aimed at a global media organization. In addition to its size (300 Gbps), it also employed several attack vectors.

"The initial attacks were TCP SYN and NULL Floods consisting of packets with invalid flag combinations (in some cases no flags defined) that grew to 35 Gbps in size and 91 Mpps in volume. Once this attack vector was mitigated, the attack type morphed into a UDP flood that grew to a peak of approximately 300 Gbps and 24 Mpps," the company explained in its report. "The attack came in multiple waves that were very short in duration but high in intensity. In one 24-hour period Verisign recorded more than 30 attacks in the 200+ Gbps range."

The complete Q2 2014 DDoS Trends Report is available online along with an infographic (PDF) that sums up the company's findings for this period.

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Eduard Kovacs (@EduardKovacs) is a contributing editor at SecurityWeek. He worked as a high school IT teacher for two years before starting a career in journalism as Softpedia’s security news reporter. Eduard holds a bachelor’s degree in industrial informatics and a master’s degree in computer techniques applied in electrical engineering.