Microsoft: Azure customer hit by record DDoS attack in August

Microsoft has mitigated a record 2.4 Tbps (terabits per second) Distributed Denial-of-Service (DDoS) attack targeting a European Azure customer during the last week of August.

"This is 140 percent higher than 2020's 1 Tbps attack and higher than any network volumetric event previously detected on Azure," said Amir Dahan, a Senior Program Manager for Azure Networking, also describing it as a User Datagram Protocol (UDP) reflection attack.

The huge DDoS attack was launched using roughly 70,000 bots, mainly across the Asia-Pacific region (e.g., Malaysia, Vietnam, Taiwan, Japan, and China) and from the United States.

The attackers hit Azure's infrastructure in terse bursts over a 10 minutes timeframe, each of these bursts reaching terabit volumes.

Dahan added that three attack peaks stood out, with the first reaching the maximum throughput at 2.4 Tbps and the subsequent going up to 0.55 Tbps and 1.7 Tbps.

The August DDoS attack came after Microsoft reported a 25 percent increase in attacks compared to 2020 Q4, with a decline in maximum volumetric throughput, from 1Tbps in 2020 Q3 to 625 Mbps in the first half of 2021.

DDoS attacks are ramping up

Distributed Denial-of-Service (DDoS) attacks ramping up significantly in both complexity and volume matches the surge in internet activity after the onset of the current COVID-19 pandemic.

In early August, Alethea Toh, a Program Manager for Azure Networking, said that Microsoft recorded a sharp increase in daily DDoS attacks in the first six months of 2021, with a rise of 25% compared to Q4 2020.

During that time, the Azure DDoS Protection team mitigated more than 251,944 unique attacks targeting Azure's global infrastructure in the first half of 2021.

The largest attack bandwidth that hit Azure's infrastructure during the first six months of 2021 was 625 Gbps, almost half of a 1 Tbps DDoS attack mitigated in Q3 2020.

Despite this, the average attack targeting Azure until the end of June has increased by 30 percent, going up from 250 Gbps to 325 Gbps.

Azure customers in the United States (59%), Europe (19%), and East Asia (6%) regions are still the most heavily targeted mostly due to the high concentration of gaming industries and financial services in these regions.

Previous record-breaking and publicly reported DDoS attacks were a 2.3Tbps volumetric strike detected by Amazon Web Services Shield in Q1 2020 and a 21.8 million requests per second (rrps) application layer assault that hit the Russian internet giant Yandex last month.

Google also mitigated a 2.54 Tbps DDoS back in 2017 as revealed by Google Security Reliability Engineer Damian Menscher in 2020.