Mumblehard Malware


Mumblehard malware is a type of malicious software that targets Linux and Unix-based web servers. It primarily functions as a spam-sending bot, utilizing infected servers to send out massive amounts of spam emails. Additionally, it employs stealth tactics to avoid detection and removal, making it particularly challenging for administrators to mitigate its effects.

Key Takeaways

  1. Mumblehard Malware is a type of Linux-based malware known for targeting servers by launching spam email campaigns and conducting DDoS attacks.
  2. The malware is self-updating and well-concealed, making it difficult to detect and mitigate, as it can remain hidden within an infected system and avoid conventional detection methods.
  3. Mumblehard Malware was first discovered in 2015 by ESET researchers, and its swift takedown in 2016 was a collaborative effort between security researchers, the open-source community, and law enforcement agencies.


The technology term “Mumblehard Malware” is important because it represents a specific type of malware that targets Linux operating systems, particularly Linux web servers.

Discovered in 2015, Mumblehard malware was known for its spamming operations and incorporating backdoor functionalities, enabling cybercriminals to gain unauthorized control of infected systems.

Mumblehard malware is heavily obfuscated, making it difficult to detect and posing a significant risk to businesses and organizations that rely on Linux infrastructure.

This malware highlights the importance of ensuring robust security for all types of operating systems, as well as the need to be aware of and address emerging threats to maintain optimal cybersecurity.


Mumblehard malware is a sophisticated and stealthy cyber security threat that was first discovered in 2015. Its primary purpose is to infiltrate Linux-based web servers and transform them into spam-distributing bots. By doing so, cybercriminals who control this malware can send out vast amounts of spam emails, ultimately evading detection while achieving their malicious intentions.

The creators of Mumblehard malware aim to obtain financial benefits by flooding inboxes with deceptive messages that commonly contain various forms of scams, phishing attempts, or advertising disreputable products and services. The Mumblehard malware consists of two main components: a backdoor and a spamming daemon. The backdoor enables the attacker to access the infected server, maintain control, and update the malware without the victim’s knowledge.

Meanwhile, the spamming daemon is responsible for orchestrating the spam email campaigns. Mumblehard malware exhibits stealthy behavior, making it difficult for victims to detect its presence; it often incorporates obfuscation techniques and encryption to conceal its code. In order to combat Mumblehard and protect web servers from this persistent threat, security professionals recommend regular server updates, real-time monitoring, and the deployment of strong cyber security solutions that focus on the detection and removal of malware.

Examples of Mumblehard Malware

Mumblehard Malware is a type of Linux-based malware that targets servers running Linux operating systems, particularly those managing websites and email services. Crypto mining and sending spam emails are two primary activities facilitated by Mumblehard. Even though specific real-world examples involving individual organizations may not be publicly disclosed, here are three instances where Mumblehard malware has been reported or encountered:

Mumblehard Takedown (2016): In October 2015, ESET researchers revealed their findings on the Mumblehard malware, and through a collaborative effort with law enforcement, managed to dismantle its command and control infrastructure in

This helped to neutralize the malware’s impact and reduce the likelihood of future attacks.

Yellsoft – DirectMailer Connection: Researchers found that Mumblehard used a Perl script to facilitate email spamming. By analyzing the malware, they discovered links to Yellsoft’s DirectMailer software. This connection suggested that the malware was potentially utilized to send spam emails and promote unauthorized software.

Spam Campaigns: Mumblehard is often associated with various spam campaigns that send emails containing malware payloads or links to malicious websites. Though specific incidents may not be widely publicized, occurrences of Mumblehard used in spam campaigns have been documented in various cybersecurity research findings. These campaigns primarily targeted Linux-based web servers and aimed to exploit them for financial gains through activities like crypto mining.

Mumblehard Malware FAQ

What is Mumblehard Malware?

Mumblehard Malware is a type of malicious software that targets Linux-based systems. It is known for exploiting vulnerabilities in PHP, mailing the server components, and scripting a backdoor to launch spam campaigns and Distributed Denial of Service (DDoS) attacks.

How does Mumblehard Malware infect systems?

Mumblehard Malware primarily infects systems through outdated software, mainly vulnerable WordPress plugins and themes. Attackers often use automated tools to search for such vulnerabilities and install the malware once they gain access.

What are the symptoms of a Mumblehard Malware infection?

Some common symptoms of a Mumblehard Malware infection include increased server load, sudden decrease in website performance, unauthorized admin access, and an influx of spam emails being sent from your server.

How to prevent a Mumblehard Malware infection?

To prevent a Mumblehard Malware infection, regularly update your software, plugins, and themes. Use strong and unique passwords for admin accounts, and install a reputable security solution to scan and monitor your server for any suspicious activity.

How can you remove Mumblehard Malware from an infected system?

If you suspect a Mumblehard Malware infection, it’s essential to act quickly. Disconnect the affected system from the internet, perform a thorough scan using a reliable antivirus tool, and clean the infected files. Additionally, change all admin passwords and review user access to ensure no unauthorized parties have gained access to your system. Once the system is secured, reconnect to the internet and continue monitoring for any signs of recurrence.

Related Technology Terms

  • Spam email campaigns
  • Linux servers
  • Backdoor Trojan
  • Perl-based botnet
  • Command and control server

Sources for More Information

  • Symantec: A global leader in cybersecurity, offering detailed information on various types of malware, including Mumblehard malware.
  • McAfee: A well-known cybersecurity company that provides extensive information on threats, including Mumblehard malware.
  • Kaspersky: A leading cybersecurity and anti-virus provider, with information on many malware types, including Mumblehard.
  • Sophos: A renowned cybersecurity company that provides comprehensive resources on various cybersecurity threats, including Mumblehard malware.

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