MCCrash botnet targets private Minecraft servers, Microsoft warns

Microsoft announced that a botnet dubbed MCCrash is launching distributed denial-of-service (DDoS) attacks against private Minecraft servers.

Microsoft spotted a cross-platform botnet, tracked as MCCrash, which has been designed to launch distributed denial-of-service (DDoS) attacks against private Minecraft servers. The IT giant tracks this cluster of activity as DEV-1028.

The experts report that the botnet originates from malicious software downloads on Windows devices, but it supports a propagating mechanism to infect multiple Linux-based devices.

MCCrash enumerates default credentials on Internet-exposed Secure Shell (SSH)-enabled devices.

“The botnet’s spreading mechanism makes it a unique threat, because while the malware can be removed from the infected source PC, it could persist on unmanaged IoT devices in the network and continue to operate as part of the botnet.” reads the post published by Microsoft. “The DEV-1028 botnet is known to launch distributed denial of service (DDoS) attacks against private Minecraft servers.”

The DDoS botnet was designed to target private Minecraft Java servers using crafted packets, experts believe it is behind a DDoS-for-hire service offered on forums or darknet sites.

Most of the infections have been reported in Russia, other countries where experts observed infections are Kazakhstan, Uzbekistan, Ukraine, Belarus, Czechia, Italy, India, and Indonesia.

According to Microsoft, the initial infections were caused by the installation of malicious cracking tools that purport to acquire illegal Windows licenses.

Once the “craking tool” is launched, it executes a PowerShell command to download and launch a fake version of svchost.exe.

The cracking tools contain additional code that downloads and launches a fake version of svchost.exe through a PowerShell command. In some cases, the downloaded file is named svchosts.exe.

Next, svchost.exe launches, which is the main Python script that contains all the botnet logic. The malicious code scans the web for systems running Debian, Ubuntu, CentOS, and IoT workloads such as Raspbian, then launches a dictionary attack to propagate.

Once a device is found, the bot downloads the file from repo[.]ark—event[.]net onto the device to create the file fuse. Then, the fuse file downloads a copy of onto the device.

“Based on our analysis, the botnet is primarily used to launch DDoS attacks against private Minecraft servers using known server DDoS commands and unique Minecraft commands.” continues the report. Below are some supported commands specifically designed to target Minecraft servers.

ATTACK_RAKNETAttack on RakNet protocol (used by Minecraft servers)
ATTACK_NETTYMinecraft – Login handshake Packet
ATTACK_[MCBOT|MINE]Minecraft – Login Start Packet
ATTACK_[MCPING|PING]Minecraft – Login Success Packet
ATTACK_MCDATAMinecraft – Login Handshake, Login Start and Close Window Packets
ATTACK_MCCRASHMinecraft – Login Handshake and Login Start packets, using Username with env variable

The ATTACK_MCCRASH command sends ${env:random payload of specific size:-a} as the username in order to saturate the resources of the server and make it crash.

The analysis of the malware revealed that it was designed to target Minecraft server 1.12.2 version, however, the experts speculate all versions between 1.7.2 and 1.18.2 can be affected by this attack. 

“The wide range of at-risk Minecraft servers highlights the impact this malware could have had if it was specifically coded to affect versions beyond 1.12.2. The unique ability of this threat to utilize IoT devices that are often not monitored as part of the botnet substantially increases its impact and reduces its chances of being detected.” concludes the post.

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Pierluigi Paganini

(SecurityAffairs – hacking, botnet)

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Pierluigi Paganini: Pierluigi Paganini is member of the ENISA (European Union Agency for Network and Information Security) Threat Landscape Stakeholder Group and Cyber G7 Group, he is also a Security Evangelist, Security Analyst and Freelance Writer. Editor-in-Chief at "Cyber Defense Magazine", Pierluigi is a cyber security expert with over 20 years experience in the field, he is Certified Ethical Hacker at EC Council in London. The passion for writing and a strong belief that security is founded on sharing and awareness led Pierluigi to find the security blog "Security Affairs" recently named a Top National Security Resource for US. Pierluigi is a member of the "The Hacker News" team and he is a writer for some major publications in the field such as Cyber War Zone, ICTTF, Infosec Island, Infosec Institute, The Hacker News Magazine and for many other Security magazines. Author of the Books "The Deep Dark Web" and “Digital Virtual Currency and Bitcoin”.

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