New Mirai Variant Hijacks Enterprise Linux Servers for DDoS Attacks

Researchers at Netscout have discovered a new variant of Mirai – a malicious software (malware) once known for hijacking hundreds of thousands of Internet of Things (IoT) devices, including wireless cameras, routers and digital video recorders, to conduct powerful distributed denial-of-service (DDoS) attacks.

Instead of infecting IoT devices, researchers at Netscoutsaid that the new Mirai variant infects non-IoT devices, in particular, enterprise Linux servers running Apache Hadoop YARN, to serve as DDoS bots.

The original Mirai malware, at its peak, infected hundreds of thousands of IoT devices, controlling these infected IoT devices as botnet to conduct high-impact DDoS attacks. Botnet refers to a group of computers controlled by attackers without the knowledge and consent of the owners to conduct malicious activities, including DDoS attacks. In a DDoS attack, the botnet or controlled computers act in unison, flooding the internet connection of a target, for instance, a particular website.

The original Mirai first came to public attention when it launched a DDoS attack against the website of journalist Brian Krebson September 20, 2016. A few days after, on September 30, the source code of Mirai was publicly released on the English-language hacking community Hackforums by a user using the screen name “Anna-senpai”.

Paras Jha, 22, the person behind Anna-senpai, pleaded guilty for co-creating Mirai. According to the U. S. Department of Justice, from December 2016 to February 2017, Jha along with his 2 college-age friends Josiah White and Dalton Norman, admitted that they successfully infected more than 100,000 IoT devices, such as home internet routers, with Mirai malware and used the hijacked IoT devices to form a powerful DDoS botnet.

Since the public release of the source code of Mirai, a number of Mirai variants have been created and released into the wild. According to Netscout researchers, this latest Mirai variant “is the first time we’ve seen non-IoT Mirai in the wild”.

How the Latest Mirai Variant Works?

To deliver the latest Mirai variant, attackers exploit the security vulnerability of Apache Hadoop YARN.

Apache Hadoop is an open source software framework that enables a cluster or group of computers to communicate and work together to store and process large amounts of data in a highly distributed manner. Meanwhile, YARN, which stands for Yet Another Resource Negotiator, is a key feature of Hadoop that helps in job scheduling of various applications and resource management in the cluster.

According to Netscout researchers, the latest Mirai malware will exploit unpatched Linux servers running on Apache Hadoop YARN, and will attempt to brute-force – attacks that systematically attempt to guess the correct username and password combination – the factory default username and password of the Hadoop YARN server.

DemonBot Vs. Latest Mirai Variant

Researchers at Radwaredetected last month another malware called “DemonBot” that infects Hadoop clusters by leveraging YARN’s unauthenticated remote command execution.

The main similarity between DemonBot and the latest Mirai variant is that both malware exploit the Hadoop YARN security vulnerability in order to infect computers. Both malware programs also turn infected computers as botnet for the purpose of launching DDoS attacks.

Enterprise Linux servers running Apache Hadoop YARN infected by DemonBot and the latest Mirai variant are dangerous as these servers account for large volumes of DDoS traffic.

The main difference between DemonBot and the latest Mirai variant is that DemonBot spreads only via central servers and doesn’t expose worm-like behavior exhibited by Mirai variants. Mirai’s worm-like behavior – its ability to spread itself within networks without user interaction – makes it a more dangerous malware than DemonBot.

According to Radware researchers, as of late October, this year, attackers attempted to exploit the Hadoop YARN vulnerability to deliver the DemonBot at an aggregated rate of over 1 million per day. 

Original Mirai Vs. Latest Mirai Variant

According to Netscout researchers, the latest Mira variant behaves much like the original Mirai. This means that both have worm-like behavior and enslaves infected computers for the purpose of launching DDoS attacks.

The main difference between the original Mirai and the latest Mirai variant is that while the original Mirai runs on IoT devices, the latest Mirai variant runs on Linux servers, in particular, those running Apache Hadoop YARN.

“Linux servers in datacenters have access to more bandwidth than IoT devices on residential networks, making them much more efficient DDoS bots,” researchers at Netscout said. ”A handful of well-resourced Linux servers can generate attacks that compete with a much larger IoT botnet.”

According to Netscout researchers, there are tens of thousands of attempts per day to exploit the Hadoop YARN vulnerability to deliver the latest Mirai variant.

Prevention

The risk of further cyberattacks is high for machines infected by malware like Mirai. To prevent attackers from hijacking your organization’s Linux servers running Apache Hadoop YARN for DDoS attacks, make sure to configure your YARN’s access control by using strong username and password combination.

Also, keep all your organization’s software up-to-date and prevent brute-force attacks by implementing an account lockout policy. For instance, after a certain number of failed login attempts, the account is locked out until an administrator unlocks it.

By leveraging the security vulnerability in enterprise Linux servers running Apache Hadoop YARN, attackers can generate much powerful DDoS attacks. Protect your organization’s online resources like websites from DDoS attacks by using an easy to use, cost-effective and comprehensive DDoS protection.

Contact us todayif you need assistance in protecting your organization’s network from malware like Mirai and protecting your organization’s online resources from DDoS attacks.