DDoS Attacks Continue to Be Complex and Unpredictable, Says VeriSign

Distributed denial-of-service (DDoS) attacks continue to be complex and unpredictable, making them more challenging for companies to mitigate, global domain and Internet service provider VeriSign said on Wednesday.

DDoS attacks attempt to cripple machines or network resources by flooding them with requests from multiple IP addresses. Out of all the VeriSign customers targeted by DDoS attacks, 41 percent were targeted multiple times during the quarter.

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"User Datagram Protocol (UDP), flood attacks continue to dominate in third quarter of this year, making up 49 percent of the total attacks," VeriSign said.

The most common UDP floods mitigated were Domain Name System (DNS) reflection attacks, followed by Network Time Protocol (NTP) reflection attacks.

The highest intensity flood attack observed by VeriSign was a TCP SYN flood that peaked at approximately 60Gbps and 150Mpps.

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This flood attack is one of the highest packets per second attacks ever observed by VeriSign, surpassing the previous highest flood of 125Mpps mitigated by VeriSign in the fourth quarter of 2015.

The largest attack in the third quarter of 2016 utilised the Generic Routing Encapsulation (GRE) protocol (IP protocol 47) and peaked at 250+ Gbps and 50+ Mpps.