Security Experts:

Storm of Large DDoS Attacks Landed in First Half of 2014

The first half of the year has been a busy one when it comes to battling distributed denial-of-service attacks.

According to Arbor Networks, the first six months of 2014 saw the most volumetric DDoS attacks ever, with more than 100 events of more than 100 GB/sec reported. In addition, there have been twice as many events of more than 20 GB/sec compared to all of 2013.

"As sites and services implement better protection from the DDoS threat attackers have to modify the mechanisms they use to achieve their goals," said Darren Anstee, director of solutions architects for Arbor Networks. "Last year, and so far this year, attackers seem to have refocused on using volumetric attacks to effectively cut their targets off from the Internet by saturating their Internet connectivity. By doing this attackers are reducing the effectiveness of the network-perimeter defenses that organizations have put in place, as cloud or ISP-based DDoS mitigation services are required to deal with these higher magnitude attacks."

However, the mechanisms being used to produce the large volumetric attacks the company is seeing are not new, he added. Reflection/amplification techniques have been around and in use by attackers for many years.

"What we have seen happen over the past year is an example of the proliferation of attack tools and information within the cyber-criminal community," he said. "Last year we saw the Spamhaus DDoS attack at around 309 Gbps using DNS reflection/amplification, the same attack vector that had been responsible for the largest attacks seen in previous years. Following the publicity around this attack we then saw a significant spike in DNS reflection/amplification activity, as attack tools and lists of servers offering good amplification factors circulated - effectively the cyber-criminal community leveraged the information available to them to achieve their goals."

Just before Christmas of 2013, the company observed some large NTP (Network Time Protocol) reflection attacks targeting gaming sites and services. Then in the first and second quarters of 2014, researchers saw a massive spike in NTP reflection activity again. The scope of those NTP reflection attacks however dipped since the first quarter of the year with average NTP traffic volumes falling back globally - but still not to the levels of November 2013.

The second quarter of 2014 saw very few large attacks, with the average attack size down by 47 percent compared to the first three months of the year. The largest attack during the second quarter was 154.69 GB/sec. That number is down from 101 percent from the first quarter.

Cybercriminals constantly evolve the way in which they attack sites and evade defenses, Anstee said.

"Given that there has been significant publicity around various successful reflection/amplification attacks, the underlying techniques are not complex, there is a large amount of infrastructure out there that can be leveraged, many network operators do not implement anti-spoofing filters and there are tools circulating, it is no surprise that these techniques are being utilized more and more."