Attackers carry out an advanced reconnaissance method to covertly gathers information about mission-critical IP address and inject pieces of attack traffic with the legitimate traffic to evade detection.
Nexusguard called this stealthy attack as bit-and-piece which is different from the regular volumetric or pulse wave attack.
“Bit-and-piece exploits the large attack surfaces of ASN-level CSPs, whereas traditional attacks zero in on one or a few IPs that serve mission-critical services such as websites and mail servers and overwhelm the target by sending the voluminous amount of junk.”
According to Nexusguard report, around 527 class c networks were targeted in the campaign and the targeted networks are within the same geo-location. The amplification attacks are the dominant one in the third quarter and ISps are the prime target in the attack.
Following are the top three attack vectors SSDP(34.35%), UDP Attacks(29.02 %) and ICMP Attacks (10.34 %). The bit-and-piece particularly abuses UDP port to generate small-sized SSDP attacks and distribute them over a large number of IP address.
Like Mongol troops in the past, attackers conducted reconnaissance missions to map out the network landscape in advance and identify the mission-critical IP ranges of targeted CSPs.
The average size of an attack is 0.972Gbps and the average attack duration is 184.23 minutes. China ranks number one in the attack source distribution followed by U.S and Vietnam.
“The ongoing evolution of DDoS methods suggests that CSPs need to enhance their network security posture and find better ways to protect their critical infrastructure and their tenants.”