The number of distributed denial-of-service (DDoS) attacks nearly doubled between the fourth quarter of 2018 and fourth quarter of 2019, researchers found in a new study of DDoS trends.
Last quarter brought an increase in the number of attacks relative to the third quarter of 2019, Kaspersky Labs researchers report, and attacks also lasted longer. This was expected, they said, as the fourth quarter is often a period of "retail warfare," driving cybercrime between October and December. The end of 2018 was "very calm" and set an expectation for a 2019 increase. However, researchers did not notice a spike in DDoS activity around Black Friday or Christmas.
DDoS attackers continued to leverage non-standard protocols for amplification attacks in the last quarter of 2019, researchers found. Adversaries have also adopted Apple Remote Management Service (ARMS), part of the Apple Remote Desktop (ARD) application for remote administration. This tactic was first spotted in June 2019; by October, attacks were widespread.
The fourth quarter of 2019 brought multiple high-profile DDoS attacks, including threats against financial organizations in South Africa, Singapore, and nations across Scandinavia. DDoS attacks aimed to cause disruption for the United Kingdom's Labour party and also targeted Minecraft servers at the Vatican. In a more recent case, just last week the FBI warned of a potential DDoS attack targeting a state-level voter registration and information site.
"This demonstrates that DDoS is still a common attack method among cybercriminals driven by ideological motives or seeking financial gain, and organizations should be prepared for such attacks and have a deep understanding of how they evolve," researchers said in a statement.
Other notable findings include a rise in "smart" DDoS attacks that focus on the application layer and are launched by skilled attackers. Researchers saw about 28% of DDoS attacks occurred on weekends. Sundays, in particular, proved popular, with 13% of attacks on this day of the week. While it may not seem significant, Sundays have historically been the quietest for DDoS activity and have been growing increasingly popular throughout 2019.
Researchers detected a growing number of peer-to-peer botnets in the past quarter; these operate independent of command-and-control servers and are more difficult to neutralize. One of these botnets, discovered by 360 Netlab researchers, is named Roboto and targets Linux servers. Another, Mozi, typically targets IoT devices and spreads using the DHT protocol.
Some adversaries continue to leverage proven tools and tactics in their DDoS attacks. In the fourth quarter of 2019, researchers saw a wave of TCP reflection attacks in which attackers send requests to legitimate services while appearing as the victim. The victim is overwhelmed with responses; as a result, the attackers' IP addresses don't show alerts.
While the duration of DDoS attacks may have slightly lengthened between the third and fourth quarters of 2019, Imperva data indicated a trend toward cheaper and shorter attacks overall. More than 51% of attacks lasted barely 15 minutes in 2019, and only 10% lasted between 15 to 30 minutes. Experts attribute the shift to more availability and use of DDoS-for-hire services, which let nearly anyone strike targets of their choosing with small attacks for as little as $5.
Researchers anticipate stability in DDoS attacks going forward. "Seems like the DDoS market have re-stabilized — we see no prerequisites for either a fall or further growth," they wrote in a blog post on their findings. "There have been no high-profile arrests or closures of specialized websites for quite some time, and the cryptocurrency market is not showing explosive growth."
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