A new botnet named Mēris is behind massive DDoS attack that hit Yandex

Pierluigi Paganini September 09, 2021

The massive DDoS attack that has been targeting the internet giant Yandex was powered b a completely new botnet tracked as Mēris.

The Russian Internet giant Yandex has been targeting by the largest DDoS attack in the history of Runet, the Russian Internet designed to be independent of the world wide web and ensure the resilience of the country to an internet shutdown.

The record magnitude of the massive DDoS attack was also confirmed by the US company Cloudflare, which specializes in the protection against such kinds of attacks. Curiously Yandex in partnership with third-party security firms provides its customers a DDoS protection.

The attack peaked at the unprecedented rate of 21.8 million requests per second.

Alexander Lyamin, CEO of Qrator Labs, a Yandex partner that provides DDoS protection, revealed that the DDoS attack was launched by a new DDoS botnet, tracked as Mēris (Latvian word for ‘plague’).

According to a joint investigation conducted by Yandex and Qrator Labs, the Mēris botnet is composed of approximately more than 200,000 devices.

“We see here a pretty substantial attacking force – dozens of thousands of host devices, growing. Separately, Qrator Labs saw the 30 000 host devices in actual numbers through several attacks, and Yandex collected the data about 56 000 attacking hosts.” states the post published by Qrator Labs. However, we suppose the number to be higher – probably more than 200 000 devices, due to the rotation and absence of will to show the “full force” attacking at once. Moreover, all those being highly capable devices, not your typical IoT blinker connected to WiFi – here we speak of a botnet consisting of, with the highest probability, devices connected through the Ethernet connection – network devices, primarily.”

According to the experts, the Mēris botnet is composed of highly capable devices that require an Ethernet connection.

Similarities between the attack against Yandex and the one blocked by Cloudflare lead experts into believing that both were powered by the Mēris botnet. The DDoS attack against Yandex on September 5 peaked at 21.8 million RPS.

The analysis of the sources of the attack revealed that they were devices with open ports 2000 and 5678 (2000 “Bandwidth test server” and port 5678 “Mikrotik Neighbor Discovery Protocol”), a combination that suggests the involvement of Mikrotik systems.

“Although Mikrotik uses UDP for its standard service on port 5678, an open TCP port is detected on compromised devices. This kind of disguise might be one of the reasons devices got hacked unnoticed by their owners. Based on this intel, we decided to probe the TCP port 5678 with the help of Qrator.Radar.” continues the post.

The researchers discovered 328 723 active hosts on the Internet replying to the TCP probe on port 5678, however, Linksys devices also use TCP service on the same post.

Mēris botnet

The Mēris botnet uses Socks4 proxy at the affected device (unconfirmed, although Mikrotik devices use socks4) and uses HTTP pipelining (http/1.1) technique for DDoS attacks.

“Blacklists are still a thing. Since those attacks are not spoofed, every victim sees the attack origin as it is. Blocking it for a while should be enough to thwart the attack and not disturb the possible end-user.” concludes the post. “Although it is, of course, unclear how the C2C owners for the Mēris botnet would act in the future – they could be taking advantage of the compromised devices, making 100% of its capacity (both bandwidth and processor wise) into their hands. In this case, there is no other way other than blocking every consecutive request after the first one, preventing answering the pipelined requests.”

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Pierluigi Paganini

(SecurityAffairs – hacking, botnet)

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