Muhstik (Botnet) – Malware

Overview

Muhstik malware represents a significant threat in the cybersecurity landscape, particularly noted for its impact on message queuing services and IoT devices. Discovered in 2017 and part of the Kaiten family of malware, Muhstik has evolved to become a potent tool for cybercriminals. It is especially notorious for its dual functionality, enabling both cryptocurrency mining and Distributed Denial of Service (DDoS) attacks. The malware’s design draws similarities to the Mirai malware, which has been widely exploited since its source code was leaked in 2016, leading to a proliferation of variants targeting various platforms.

The recent spotlight on Muhstik has come with its targeting of Apache RocketMQ, a widely used distributed messaging and streaming platform. This platform, renowned for its low latency, high performance, and scalability, is vulnerable to a remote code execution flaw identified as CVE-2023-33246. This vulnerability has been exploited by attackers to deploy Muhstik malware, leveraging its ability to download and execute malicious payloads on compromised systems.

Targets

IoT Devices: Often targeted for their security vulnerabilities and ability to be co-opted for botnet activities.

Linux-Based Servers: Particularly those with weak or misconfigured security settings.

Message Queuing Services: Such as Apache RocketMQ, which has been targeted due to known vulnerabilities.

Cryptocurrency Miners: Attackers use infected devices to mine cryptocurrencies illicitly.

Network Infrastructure: For launching Distributed Denial of Service (DDoS) attacks.

How they operate

At its core, Muhstik malware is known for exploiting vulnerabilities in public-facing applications, particularly through the Exploit Public-Facing Application tactic (T1190). One of the primary methods of initial access involves exploiting weaknesses in services such as Apache RocketMQ, an open-source messaging system. By leveraging known vulnerabilities, the malware gains unauthorized access to the target system, setting the stage for further exploitation.

Once inside the system, Muhstik employs a range of execution tactics to deploy its payload. The malware utilizes Command and Scripting Interpreter (T1059) techniques to execute shell commands or scripts, effectively running its malicious code. Additionally, it may exploit vulnerabilities in client applications to facilitate the execution of its payload, a tactic known as Exploitation for Client Execution (T1203). These methods ensure that the malware can initiate its activities even if initial access was achieved through different means.

Persistence is a crucial aspect of Muhstik’s operational strategy. The malware often Create[s] or Modify[ies] System Process (T1543), altering system files or processes to ensure that it remains active and operational across system reboots. This tactic is critical for maintaining a long-term foothold in the compromised environment, as it allows the malware to re-establish itself even after a system restart.

Privilege escalation is another key component of Muhstik’s functionality. The malware frequently utilizes Exploitation for Privilege Escalation (T1203) techniques to gain elevated privileges, enabling it to execute with higher access rights. This elevation is essential for conducting more in-depth operations, such as modifying system configurations or accessing restricted data.

In terms of defense evasion, Muhstik malware employs various techniques to avoid detection by security tools. It uses Obfuscated Files or Information (T1027) to conceal its presence, employing encryption or encoding to mask its activities. Additionally, the malware may utilize Fileless Execution (T1203) methods, running directly in memory or using temporary directories to minimize traceable footprints and evade traditional file-based detection mechanisms.

Credential access is another critical aspect of Muhstik’s operational methodology. The malware may use Brute Force (T1110) techniques to crack passwords and gain unauthorized access to systems or accounts, further facilitating its spread and control over compromised networks. This tactic enhances the malware’s ability to infiltrate additional systems and escalate its control within the target environment.

Discovery is an integral part of Muhstik’s approach, allowing it to gather detailed information about the compromised system. Through System Information Discovery (T1082), the malware collects data on system configurations and installed software, which helps tailor its attacks and optimize its operations.

Command and Control (C2) communications are managed through sophisticated channels. Muhstik utilizes Ingress Tool Transfer (T1105) to download additional tools or payloads from remote servers, expanding its capabilities and ensuring it can execute a variety of malicious activities. The malware also employs Command and Control (T1071) techniques, often using protocols like IRC to maintain communication between the infected system and the attacker’s servers.

Finally, Muhstik malware has significant impacts on its targets. It may stage data for exfiltration or other malicious purposes through Data Staged (T1074) techniques and engage in Resource Hijacking (T1496) to exploit system resources for tasks such as cryptocurrency mining. These impacts not only compromise the integrity and performance of the target systems but also have broader implications for operational security and financial resources.

MITRE Tactics and Techniques

Initial Access:

Exploit Public-Facing Application (T1190): Exploiting vulnerabilities in services like Apache RocketMQ.

Execution:

Command and Scripting Interpreter (T1059): Using shell commands or scripts to execute the malware payload.
Exploitation for Client Execution (T1203): Exploiting vulnerabilities to execute malicious code.

Persistence:

Create or Modify System Process (T1543): Modifying system files to ensure the malware persists across reboots.

Privilege Escalation:

Exploitation for Privilege Escalation (T1203): Gaining elevated privileges to execute malware with higher access.

Defense Evasion:

Obfuscated Files or Information (T1027): Using obfuscation to avoid detection by security tools.
Fileless Execution (T1203): Running malware directly in memory or using temporary directories to avoid leaving traces.

Credential Access:

Brute Force (T1110): Using brute-force techniques to gain unauthorized access.

Discovery:

System Information Discovery (T1082): Gathering information about the system to tailor attacks or spread further.

Command and Control:

Ingress Tool Transfer (T1105): Downloading additional tools or payloads from remote servers.
Command and Control (T1071): Using protocols like IRC for communication between the compromised system and the attacker’s server.

Impact:

Data Staged (T1074): Storing and preparing data for exfiltration or other malicious activities.
Resource Hijacking (T1496): Utilizing infected devices for cryptocurrency mining or other resource-intensive tasks.

Impact / Significant Attacks

Apache RocketMQ Exploitation (2023): Muhstik was observed targeting vulnerabilities in Apache RocketMQ, an open-source distributed messaging and streaming platform. Attackers exploited weaknesses in the application to deploy the malware, leading to widespread infections and data breaches in multiple organizations.

Large-Scale Cryptojacking Operations (2023-2024): Muhstik has been used in extensive cryptojacking campaigns, where it hijacks system resources to mine cryptocurrencies without the knowledge or consent of the system owners. These operations have affected both corporate and personal systems across various regions, causing significant performance degradation and financial losses.

References:

• Muhstik Malware Targets Message Queuing Services Applications
• Hands-On Muhstik Botnet: crypto-mining attacks targeting Kubernetes