August 7, 2024

How Darktrace’s AI Applies a Zero-Trust Mentality within Critical Infrastructure Supply Chains

Darktrace prevented a Critical National Infrastructure organization from falling victim to a SharePoint phishing attack originating from one of its trusted suppliers. This blog discusses common perceptions of zero-trust in email security, how AI that uses anomaly-based threat detection embodies core zero-trust principles and the relevance of this approach to securing CNI bodies with complex but interdependent supply chains from Cloud account compromise.

Written by

Nicole Wong

Cyber Security Analyst

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

Nicole Wong

Cyber Security Analyst

Aug 2024

Note: In order to name anonymity, real organization names have been replaced, all names used in this blog are fictitious.

What are critical national infrastructure sectors?

Critical National Infrastructure (CNI) sectors encompass of assets, systems, and networks essential to the functioning of society. Any disruption or destruction of these sectors could have wide-reaching and potentially disastrous effects on a country’s economy, security and/or healthcare services [1].

Cyber risks across Transportation Systems sector

Transportation Systems is one such CNI sector comprising of interconnected networks of fixed and mobile assets managed by both public and private operators. These systems are highly interdependent with other CNI sectors too. As such, the digital technologies this sector relies on – such as positioning and tracking, signaling, communications, industrial system controls, and data and business management – are often interconnected through different networks and remote access terminals. This interconnectedness creates multiple entry points that need to be security across the supply.

Digital transformation has swept through CNI sectors in recent years, including Transportation Systems. These organizations are now increasingly dependent on third-party and cloud providers for data storage and transmission, making their supply chains vulnerable to exploitation by malicious actors [2].

The exploitation of legitimate and popular cloud services mirrors the well-known “living-off-the-land” techniques, which are not being adapted to the cloud along with the resources they support. In one recent case previously discussed by Darktrace, for example, a phishing attack attempted to abuse Dropbox to deliver malicious payloads.

Zero-Trust within CNI Sectors

One recommended approach to secure an organization’s supply chain and cloud environments is the implementation of zero-trust strategies, which remove inherent trust within the network [3] [4]. The principle of “never trust, always verify” is widely recognized as an architectural design, with 63% of organizations surveyed by Gartner reportedly implementing a zero-trust strategy, but in most cases to less than 50% of their environments [5]

Although this figure reflects the reality and challenge of balancing operations and security, demands from the threat landscape and supply chain risks mean that organizations must adopt zero-trust principles in areas not traditionally considered part of network architecture, such as email and cloud environments.

Email is often the primary entry point for cyber-attacks with Business Email Compromise (BEC) being a major threat to CNI organizations. However, the application of zero-trust principles to secure email environments is still not well understood. Common misconceptions include:

“Positively identifying known and trusted senders” – Maintaining a list of “known and trusted senders” contradicts the zero-trust model, which assumes that no entity is inherently trustworthy.
“Using DMARC, DKIM and SPF” – While these protocols offer some protection, they are often insufficient on their own, as they can be bypassed and do not protect against email account takeovers. Research published from Darktrace’s last two threat reports consistently shows that at least 60% of phishing emails detected by Darktrace had bypassed Domain-based Message Authentication, Reporting & Conformance (DMARC) [6] [7].
“Mapping transaction flows between internal and external users to determine what access is required/not required” – Although this aligns with the principles of least privilege, it is too static for today’s dynamic supply chains and evolving digital infrastructure. This approach also suggests the existence of “trusted” access routes into a network.

Attack Overview

In July 2024, Darktrace / EMAIL™ detected and contained a sophisticated phishing attack leveraging Microsoft SharePoint. This attack exploited the trusted relationship between a Darktrace customer in the public transport sector and a compromised supplier. Traditional methods, such as those detailed above, would likely have failed to defend against such an advanced threat. However, Darktrace’s behavioral analysis and zero-trust approach to email security allowed it to successfully identify and neutralize the attack, preventing any potential disruption.

Initial Intrusion Attempt

The observed phishing attack by Darktrace would suggest that the customer’s supplier was targeted by a similar campaign beforehand. This initial breach likely allowed the attacker to use the now compromised account as a vector to compromise additional accounts and networks.

On July 9, Darktrace / EMAIL identified a significant spike in inbound emails from “supplier@engineeringcompany[.]com”. The emails appeared to be legitimate notifications sent via SharePoint and contained a file named “Payment Applications Docs”.

Figure 1: Email correspondence in the weeks around the phishing attack. The sender is an established correspondent with ongoing communications prior to and after the attack, however there is a significant spike in incoming emails on the day of the attack.

This reflects a common technique in malicious social engineering attempts, where references to payment are used to draw attention and prompt a response. Darktrace observed a large number of recipients within the organization receiving the same file, suggesting that the motive was likely credential harvesting rather than financial gain. Financially motivated attacks typically require a more targeted, ‘under-the-radar’ approach to be successful.

These phishing emails were able to bypass the customer’s email gateways as they were sent from a trusted and authoritative source, SharePoint, and utilized an email address with which the customer had previously corresponded. The compromised account was likely whitelisted by traditional email security tools that rely on SPF, DKIM, and DMAC, allowing the malicious emails to evade detection.

Autonomous Response

Darktrace / EMAIL analysis of the unusual characteristics of the phishing email in relation to the supplier’s typical behaviour, despite the email originating from a legitimate SharePoint notification. — Figure 2: Darktrace / EMAIL analysis of the unusual characteristics of the phishing email in relation to the supplier’s typical behavior, despite the email originating from a legitimate SharePoint notification.

However, Darktrace / EMAIL did not use these static rules to automatically trust the email. Darktrace’s Self-Learning AI detected the following anomalies:

Although the sender was known, it was not normal for the supplier to share files with the customer via SharePoint.
The supplier initiated an unusually large number of file shares in a short period of time, indicating potential spam activity.
The SharePoint link had wide access permissions, which is unusual for a sensitive payment document legitimately shared between established contacts.

Darktrace understood that the email activity constituted a significant deviation in expected behavior between the sender and customer, regardless of the known sender and use of a legitimate filesharing platform like SharePoint.

As a result, Darktrace took action to hold more than 100 malicious emails connected to the phishing attack, preventing them from landing in recipient inboxes in the first instance. By taking a behavioral approach to securing customer email environments, Darktrace’s Self-Learning AI embodies the principles of zero trust, assessing each interaction in real-time against a user’s dynamic baseline rather than relying on static and often inaccurate rules to define trust.

Conclusion

Cloud services, such as SharePoint, offer significant advantages to the transportation sector by streamlining data exchange with supply chain partners and facilitating access to information for analytics and planning. However, these benefits come with notable risks. If a cloud account is compromised, unauthorized access to sensitive information could lead to extortion and lateral movement into mission-critical systems for more damaging attacks on CNI. Even a brief disruption in cloud access can have severe economic repercussions due to the sector’s dependence on these services for resource coordination and the cascading impacts on other critical systems [9].

While supply chain resilience is often evaluated based on a supplier’s initial compliance with baseline standards, organizations must be wary of potential future threats and focus on post-implementation security. It is essential for organizations to employ strategies to protect their assets from attacks that would exploit vulnerabilities within the trusted supply chain. Given that CNI and the transportation sector are prime targets for state-sponsored actors and Advanced Persistent Threat (APT) groups, the complex and interconnected nature of their supply chains opens the door for opportunistic attackers.

Defenders face the challenge of ensuring secure access and collaboration across numerous, dynamic assets, often without full visibility. Therefore, security solutions must be as dynamic as the threats they face, avoiding reliance on static rules. Real-time assessment of devices behavior, even if deemed trusted by end-users and human security teams, is crucial for maintaining security.

Darktrace’s AI-driven threat detection aligns with the zero-trust principle of assuming the risk of a breach. By leveraging AI that learns an organization’s specific patterns of life, Darktrace provides a tailored security approach ideal for organizations with complex supply chains.

Credit to Nicole Wong, Senior Cyber Analyst Consultant and Ryan Traill, Threat Content Lead

Appendices

Darktrace Model Detections

Key model alerts:

Personalized Sharepoint Share + New Unknown Link
Personalized Sharepoint Share + Bad Display Text
Personalized Sharepoint Share + Distant Recipient Interaction with Domain
Personalized Sharepoint Share + Sender Surge
Personalized Sharepoint Share + Wide Access Sharepoint Link

MITRE ATT&CK Mapping

Resource Development • Compromise Accounts: Cloud Accounts • T1586.003

Initial Access • Supply Chain Compromise • T1195

References

[1] https://www.cisa.gov/topics/critical-infrastructure-security-and-resilience/critical-infrastructure-sectors

[2] https://committees.parliament.uk/writtenevidence/126313/pdf/

[3] https://nvlpubs.nist.gov/nistpubs/SpecialPublications/NIST.SP.800-161r1.pdf

[4] https://cloudsecurityalliance.org/press-releases/2023/11/15/cloud-security-alliance-launches-the-industry-s-first-authoritative-zero-trust-training-and-credential-the-certificate-of-competence-in-zero-trust-cczt

[5] https://www.gartner.com/en/documents/5286863#:~:text=Summary,anticipate%20staffing%20and%20cost%20increases.

[6] https://darktrace.com/threat-report-2023

[7] https://darktrace.com/resources/first-6-half-year-threat-report-2024

[8] https://dfrlab.org/2023/07/10/critical-infrastructure-and-the-cloud-policy-for-emerging-risk/#transportation

[9] https://access-national-risk-register.service.cabinetoffice.gov.uk/risk-scenario/cyber-attack-transport-sector

Written by

Nicole Wong

Cyber Security Analyst

Inside the SOC

Written by

Nicole Wong

Cyber Security Analyst

VP, Security & AI Strategy, Field CISO

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Endpoint

January 30, 2026

ClearFake: From Fake CAPTCHAs to Blockchain-Driven Payload Retrieval

fake captcha to blockchain driven palyload retrieval

What is ClearFake?

As threat actors evolve their techniques to exploit victims and breach target networks, the ClearFake campaign has emerged as a significant illustration of this continued adaptation. ClearFake is a campaign observed using a malicious JavaScript framework deployed on compromised websites, impacting sectors such as e‑commerce, travel, and automotive. First identified in mid‑2023, ClearFake is frequently leveraged to socially engineer victims into installing fake web browser updates.

In ClearFake compromises, victims are steered toward compromised WordPress sites, often positioned by attackers through search engine optimization (SEO) poisoning. Once on the site, users are presented with a fake CAPTCHA. This counterfeit challenge is designed to appear legitimate while enabling the execution of malicious code. When a victim interacts with the CAPTCHA, a PowerShell command containing a download string is retrieved and executed.

Attackers commonly abuse the legitimate Microsoft HTML Application Host (MSHTA) in these operations. Recent campaigns have also incorporated Smart Chain endpoints, such as “bsc-dataseed.binance[.]org,” to obtain configuration code. The primary payload delivered through ClearFake is typically an information stealer, such as Lumma Stealer, enabling credential theft, data exfiltration, and persistent access [1].

Darktrace’s Coverage of ClearFake

Darktrace / ENDPOINT first detected activity likely associated with ClearFake on a single device on over the course of one day on November 18, 2025. The system observed the execution of “mshta.exe,” the legitimate Microsoft HTML Application Host utility. It also noted a repeated process command referencing “weiss.neighb0rrol1[.]ru”, indicating suspicious external activity. Subsequent analysis of this endpoint using open‑source intelligence (OSINT) indicated that it was a malicious, domain generation algorithm (DGA) endpoint [2].

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Figure 1: The process line referencing weiss.neighb0rrol1[.]ru, as observed by Darktrace / ENDPOINT.

This activity indicates that mshta.exe was used to contact a remote server, “weiss.neighb0rrol1[.]ru/rpxacc64mshta,” and execute the associated HTA file to initiate the next stage of the attack. OSINT sources have since heavily flagged this server as potentially malicious [3].

The first argument in this process uses the MSHTA utility to execute the HTA file hosted on the remote server. If successful, MSHTA would then run JavaScript or VBScript to launch PowerShell commands used to retrieve malicious payloads, a technique observed in previous ClearFake campaigns. Darktrace also detected unusual activity involving additional Microsoft executables, including “winlogon.exe,” “userinit.exe,” and “explorer.exe.” Although these binaries are legitimate components of the Windows operating system, threat actors can abuse their normal behavior within the Windows login sequence to gain control over user sessions, similar to the misuse of mshta.exe.

EtherHiding cover

Darktrace also identified additional ClearFake‑related activity, specifically a connection to bsc-testnet.drpc[.]org, a legitimate BNB Smart Chain endpoint. This activity was triggered by injected JavaScript on the compromised site www.allstarsuae[.]com, where the script initiated an eth_call POST request to the Smart Chain endpoint.

Figure 2: Example of a fake CAPTCHA on the compromised site www.allstarsuae[.]com.

EtherHiding is a technique in which threat actors leverage blockchain technology, specifically smart contracts, as part of their malicious infrastructure. Because blockchain is anonymous, decentralized, and highly persistent, it provides threat actors with advantages in evading defensive measures and traditional tracking [4].

In this case, when a user visits a compromised WordPress site, injected base64‑encoded JavaScript retrieved an ABI string, which was then used to load and execute a contract hosted on the BNB Smart Chain.

Figure 3: JavaScript hosted on the compromised site www.allstaruae[.]com.

Conducting malware analysis on this instance, the Base64 decoded into a JavaScript loader. A POST request to bsc-testnet.drpc[.]org was then used to retrieve a hex‑encoded ABI string that loads and executes the contract. The JavaScript also contained hex and Base64‑encoded functions that decoded into additional JavaScript, which attempted to retrieve a payload hosted on GitHub at “github[.]com/PrivateC0de/obf/main/payload.txt.” However, this payload was unavailable at the time of analysis.

Figure 4: Darktrace’s detection of the POST request to bsc-testnet.drpc[.]org.

Figure 5: Darktrace’s detection of the executable file and the malicious hostname.