Huge DDoS attacks are becoming a regular occurrence with over 100 incidents breaching the psychological 100Gbps barrier that used to be seen as signifying trouble, new figures from Arbor Networks have confirmed.
Arbor's numbers drawn from its Atlas monitoring of traffic through 290 global ISPs show a consistent upward trend on such volumetric attacks at every point on the scale in the last year, with a doubling in the number of attacks over 20Gbps compared to 2013.
But super-massive 100Gbps attacks soared to 111 for the first half of 2014, mostly concentrated in Q1 which accounted for 72 on its own. As it happens, the largest attack in Q2 specifically was a 154Gbps NTP amplification assault on a Spanish data centre, which looks small compared to the 325Gbps monster that struck CloudFlare in February.
To put this into perspective, two to three years ago news of an attack exceeding 100Gbps would have been news in its own right but such events are now being detected around four times a week.
NTP (Network Time Protocol) attacks came out of nowhere late in 2013, following on from the fashion of using DNS amplification that started with the notorious assault on anti-spam organisation Spamhaus in March of that year.
In a spot of good news, the fashion for NTP seems to have abated slightly for now, presumably because defenders have woken up to the amplification vulnerability that made such attacks possible. NTP is still the protocol of choice for large attacks, accounting for almost half of the attacks of 100Gbps or higher.
Along with DNS and NTP, two other protocols that attackers have abused are SNMP (Simple Network Management Protocol), used to manage network devices, and Chargen (Character Generator Protocol), used for debugging. As with NTP, both have been around for donkey's years and their potential to be used in DDoS pretty much ignored.
SNMP accounted for only 0.1 percent of the DDoS attacks seen by Arbor in Q2 while Chargen represented 1.4 percent.
"Following on from the storm of NTP reflection attacks in Q1 volumetric DDoS attacks continued to be a problem well into the second quarter, with an unprecedented 100 attacks over 100GB/sec reported so far this year," commented Arbor's director of solutions architecture, Darren Anstee.
"The frequency of very large attacks continues to be an issue, and organisations should take an integrated, multi-layered approach to protection. Even organisations with significant amounts of Internet connectivity can now see that capacity exhausted relatively easily by the attacks that are going on out there."
Working out what DDoS statistic mean in concrete terms is like nailing a large jelly to a small wall. It's obvious perhaps that DDoS attacks are on an upward trajectory in average size, diversity, opportunism and frequency; that has been true for some years. But defences are also better which might be a root cause for the growth in very large attacks as DDoS criminals work that bit harder to cause the same trouble.
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