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August 22, 2024

From the Depths: Analyzing the Cthulhu Stealer Malware for macOS

Cado Security (now part of Darktrace) analyzed "Cthulhu Stealer," a macOS malware-as-a-service written in Go. It impersonates legitimate software, prompts for user and MetaMask passwords, and steals credentials, cryptocurrency wallets, and game accounts. Functionally similar to Atomic Stealer, Cthulhu was rented via an underground marketplace, but its operators faced complaints and a ban for alleged exit scamming.
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
Tara Gould
Malware Research Lead
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22
Aug 2024

Introduction

For years there has been a general belief that macOS systems are immune to malware. While MacOS has a reputation for being secure, macOS malware has been trending up in recent years with the emergence of Silver Sparrow [1],  KeRanger [2], and Atomic Stealer [3], among others. Recently, Cado Security has identified a malware-as-a-service (MaaS) targeting macOS users named “Cthulhu Stealer”. This blog will explore the functionality of this malware and provide insight into how its operators carry out their activities.

Technical analysis

File details:

Language: Go

Not signed

Stripped

Multiarch: x86_64 and arm

Screenshot
Figure 1: Screenshot of disk image when mounted

Cthulhu Stealer is an Apple disk image (DMG) that is bundled with two binaries, depending on the architecture. The malware is written in GoLang and disguises itself as legitimate software. Once the user mounts the dmg, the user is prompted to open the software. After opening the file, “osascript”, the macOS command-line tool for running AppleScript and JavaScript is used to prompt the user for their password. 

Password Prompt
Figure 2: Password Prompt 
Osascript
Figure 3: Osascript prompting user for password

Once the user enters their password, a second prompt requests the user’s MetaMask [4] password. A directory is created in ‘/Users/Shared/NW’ with the credentials stored in textfiles. Chainbreak [5] is used to dump Keychain passwords and stores the details in “Keychain.txt”.

Wallet Connect Password prompt
Figure 4: Password prompt for MetaMask
Directory
Figure 5: Directory /Users/Shared/NW with created files

A zip file containing the stolen data is created in: “/Users/Shared/NW/[CountryCode]Cthulhu_Mac_OS_[date]_[time].zip.” Additionally, a notification is sent to the C2, to alert to new logs. The malware fingerprints the victim’s system, gathering information including IP, with IP details that are retrieved from ipinfo.io.  

System information including system name, OS version, hardware and software information is also gathered and stored in a text file.

Parsed IP Details
Figure 6: Parsed IP Details 
Cthulhu Stealer
Figure 7: Contents of ‘Userinfo.txt’
Code
Figure 8: Part of the function saving system information to text file
Log Alert
Figure 9: Alert of Log that is sent to operators

Cthulhu Stealer impersonates disk images of legitimate software that include:

  • CleanMyMac
  • Grand Theft Auto IV (appears to be a typo for VI)
  • Adobe GenP

The main functionality of Cthulhu Stealer is to steal credentials and cryptocurrency wallets from various stores, including game accounts. Shown in Figure 10, there are multiple checker functions that check in the installation folders of targeted file stores, typically in “Library/Application Support/[file store]”. A directory is created in “/Users/Shared/NW” and the contents of the installation folder are dumped into text files for each store.

Code
Figure 10: “Checker” functions being called in main function
Code
Figure 11: Function BattleNetChecker

A list of stores Cthulhu Stealer steals from is shown in the list below:

  • Browser Cookies
  • Coinbase Wallet
  • Chrome Extension Wallets
  • Telegram Tdata account information
  • Minecraft user information
  • Wasabi Wallet
  • MetaMask Wallet
  • Keychain Passwords
  • SafeStorage Passwords
  • Battlenet game, cache and log data
  • Firefox Cookies
  • Daedalus Wallet
  • Electrum Wallet
  • Atomic Wallet
  • Binanace Wallet
  • Harmony Wallet
  • Electrum Wallet
  • Enjin Wallet
  • Hoo Wallet
  • Dapper Wallet
  • Coinomi Wallet
  • Trust Wallet

Comparison to atomic stealer

Atomic Stealer [6] is an information-stealer that targets macOS written in Go that was first identified in 2023. Atomic Stealer steals crypto wallets, browser credentials, and keychain. The stealer is sold on Telegram to affiliates for $1,000 per month. The functionality and features of Cthulhu Stealer are very similar to Atomic Stealer, indicating the developer of Cthulhu Stealer probably took Atomic Stealer and modified the code. The use of “osascript”  to prompt the user for their password is similar in Atomic Stealer and Cthulhu, even including the same spelling mistakes. 

Forum and operators

The developers and affiliates of Cthulhu Stealer operate as “Cthulhu Team” using Telegram for communications. The stealer appears to be being rented out to individuals for $500 USD/month, with the main developer paying out a percentage of earnings to affiliates based on their deployment. Each affiliate of the stealer is responsible for the deployment of the malware. Cado has found Cthulhu Stealer sold on two well-known malware marketplaces which are used for communication, arbitration and advertising of the stealer, along with Telegram. The user “Cthulhu” (also known as Balaclavv), first started advertising Cthulhu Stealer at the end of 2023 and appeared to be operating for the first few months of 2024, based on timestamps from the binaries. 

Various affiliates of the stealer started lodging complaints against Cthulhu in 2024 with regards to payments not being received. Users complained that Cthulhu had stolen money that was owed to them and accused the threat actor of being a scammer or participating in an exit scam. As a result, the threat actor received a permanent ban from the marketplace.

Screenshot
Figure 12: Screenshot of an arbitration an affiliate lodged against Cthulhu

Key takeaways 

In conclusion, while macOS has long been considered a secure system, the existence of malware targeting Mac users remains an increasing security concern. Although Cthulhu Team no longer appears to be active, this serves as a reminder that Apple users are not immune to cyber threats. It’s crucial to remain vigilant and exercise caution, particularly when installing software from unofficial sources.

To protect yourself from potential threats, always download software from trusted sources, such as the Apple App Store or the official websites of reputable developers. Enable macOS’s built-in security features such as Gatekeeper, which helps prevent the installation of unverified apps. Keep your system and applications up to date with the latest security patches. Additionally, consider using reputable antivirus software to provide an extra layer of protection.

By staying informed and taking proactive steps, you can significantly reduce the risk of falling victim to Mac malware and ensure your system remains secure.

Indicators of compromise

Launch.dmg  

6483094f7784c424891644a85d5535688c8969666e16a194d397dc66779b0b12  

GTAIV_EarlyAccess_MACOS_Release.dmg  

e3f1e91de8af95cd56ec95737669c3512f90cecbc6696579ae2be349e30327a7  

AdobeGenP.dmg  

f79b7cbc653696af0dbd867c0a5d47698bcfc05f63b665ad48018d2610b7e97b  

Setup2024.dmg  

de33b7fb6f3d77101f81822c58540c87bd7323896913130268b9ce24f8c61e24  

CleanMyMac.dmg  

96f80fef3323e5bc0ce067cd7a93b9739174e29f786b09357125550a033b0288  

Network indicators  

89[.]208.103.185  

89[.]208.103.185:4000/autocheckbytes  

89[.]208.103.185:4000/notification_archive  

MITRE ATTACK  

User Execution  

T1204  

Command and Scripting Interpreter: Apple Script  

T1059.002  

Credentials From Password Stores  

T1555  

Credentials From Password Stores: Keychain  

T1555.001  

Credentials From Password Stores: Credentials From Web Browser  

T1555.003  

Account Discovery   

T1087  

System Information Discovery  

T1082  

Data Staged  

T1074  

Data From Local System  

T1005  

Exfiltration Over C2 Channel  

T1041  

Financial Theft  

Detection

Yara

rule MacoOS_CthulhuStealer {   
meta:       
 Description = "Detects Cthulhu MacOS Stealer Binary"       
 author = "Cado Security"       
 date = "14/08/2024"       
 md5 = "897384f9a792674b969388891653bb58" strings:           
 $mach_o_x86_64 = {CF FA ED FE 07 00 00 01 00 00 00 00 00 00 00 00}           
 $mach_o_arm64 = {CF FA ED FE 0C 00 00 01 00 00 00 00 00 00 00 00}          $c2 = "http://89.208.103.185:4000"           
 $path1 = "/Users/Shared/NW" fullword          $path2 = "/Users/admin/Desktop/adwans/Builder/6987368329/generated_script.go" fullword          $path3 = "ic.png" fullword           
 $zip = "@====)>>>>>>>>> CTHULHU STEALER - BOT <<<<<<<<<(====@\n" fullword          $func1 = "copyKeychainFile"           
 $func2 = "grabberA1"           
 $func3 = "grabberA2"          
 $func4 = "decodeIPInfo"           
 $func5 = "battlenetChecker"           
 $func6 = "binanceChecker"          
 $func7 = "daedalusChecker"           
 $func8 = "CCopyFFolderContents"           
 $func9 = "electrumChecker"         
 
condition:         
 $mach_o_x86_64 or $mach_o_arm64           
 and any of ($func*) or any of ($path*) or ($c2) or ($zip) } 

References

[1] https://redcanary.com/blog/threat-intelligence/clipping-silver-sparrows-wings/

[2] https://unit42.paloaltonetworks.com/new-os-x-ransomware-keranger-infected-transmission-bittorrent-client-installer/

[3] https://www.sentinelone.com/blog/atomic-stealer-threat-actor-spawns-second-variant-of-macos-malware-sold-on-telegram/

[4] https://metamask.io/

[5] https://github.com/n0fate/chainbreaker

[6] https://www.sentinelone.com/blog/atomic-stealer-threat-actor-spawns-second-variant-of-macos-malware-sold-on-telegram/

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
Tara Gould
Malware Research Lead

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May 20, 2026

Prompt Security in Enterprise AI: Strengths, Weaknesses, and Common Approaches

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How enterprise AI Agents are changing the risk landscape  

Generative AI Agents are changing the way work gets done inside enterprises, and subsequently how security risks may emerge. Organizations have quickly realized that providing these agents with wider access to tooling, internal information, and granting permissions for the agent to perform autonomous actions can greatly increase the efficiency of employee workflows.

Early deployments of Generative AI systems led many organizations to scope individual components as self-contained applications: a chat interface, a model, and a prompt, with guardrails placed at the boundary. Research from Gartner has shown that while the volume and scope of Agentic AI deployments in enterprise environments is rapidly accelerating, many of the mechanisms required to manage risk, trust, and cost are still maturing.

The issue now resides on whether an agent can be influenced, misdirected, or manipulated in ways that leads to unsafe behavior across a broader system.

Why prompt security matters in enterprise AI

Prompt security matters in enterprise AI because prompts are the primary way users and systems interact with Agentic AI models, making them one of the earliest and most visible indicators of how these systems are being used and where risk may emerge.

For security teams, prompt monitoring is a logical starting point for understanding enterprise AI usage, providing insight into what types of questions are being asked and tasks are being given to AI Agents, how these systems are being guided, and whether interactions align with expected behavior. Complete prompt security takes this one step further, filtering out or blocking sensitive or dangerous content to prevent risks like prompt injection and data leakage.

However, visibility only at the prompt layer can create a false sense of security. Prompts show what was asked, but not always why it was asked, or what downstream actions were triggered by the agent across connected systems, data sources, or applications.

What prompt security reveals  

The primary function of prompt security is to minimize risks associated with generative and agentic AI use, but monitoring and analysis of prompts can also grant insight into use cases for particular agents and model. With comprehensive prompt security, security teams should be able to answer the following questions for each prompt:

  • What task was the user attempting to complete?
  • What data was included in the request, and was any of the data high-risk or confidential?
  • Was the interaction high-risk, potentially malicious, or in violation of company policy?
  • Was the prompt anomalous (in comparison to previous prompts sent to the agent / model)?

Improving visibility at this layer is a necessary first step, allowing organizations to establish a baseline for how AI systems are being used and where potential risks may exist.  

Prompt security alone does not provide a complete view of risk. Further data is needed to understand how the prompt is interpreted, how context is applied, what autonomous actions the agent takes (if any), or what downstream systems are affected. Understanding the outcome of a query is just as important for complete prompt security as understanding the input prompt itself – for example, a perfectly normal, low-risk prompt may inadvertently result in an agent taking a high-risk action.

Comprehensive AI security systems like Darktrace / SECURE AI can monitor and analyze both the prompt submitted to a Generative AI system, as well as the responses and chain-of-thought of the system, providing greater insight into the behavior of the system. Darktrace / SECURE AI builds on the core Darktrace methodology, learning the expected behaviors of your organization and identifying deviations from the expected pattern of life.

How organizations address prompt security today

As prompt-level visibility has become a focus, a range of approaches have emerged to make this activity more observable and controllable. Various monitoring and logging tools aim to capture prompt inputs to be analyzed after the fact.  

Input validation and filtering systems attempt to intervene earlier, inspecting prompts before they reach the model. These controls look for known jailbreak patterns, language indicative of adversarial attacks, or ambiguous instructions which could push the system off course.

Importantly, for a prompt security solution to be accurate and effective, prompts must be continually observed and governed, rather than treated as a point-in-time snapshot.  

Where prompt security breaks down in real environments

In more complex environments, especially those involving multiple agents or extensive tool use, AI security becomes harder to define and control.

Agent-to-Agent communications can be harder to monitor and trace as these happen without direct user interaction. Communication between agents can create routes for potential context leakage between agents, unintentional privilege escalation, or even data leakage from a higher privileged agent to a lower privileged one.

Risk is shaped not just by what is asked, but by the conditions in which that prompt operates and the actions an agent takes. Controls at the orchestration layer are starting to reflect this reality. Techniques such as context isolation, scoped memory, and role-based boundaries aim to limit how far a prompt’s influence can extend.  

Furthermore, Shadow AI usage can be difficult to monitor. AI systems that are deployed outside of formal governance structures and Generative AI systems hosted on unknown endpoints can fly under the radar and can go unseen by monitoring tools, leaving a critical opening where adversarial prompts may go undetected. Darktrace / SECURE AI features comprehensive detection of Shadow AI usage, helping organizations identify potential risk areas.

How prompt security fits in a broader AI risk model

Prompt security is an important starting point, but it is not a complete security strategy. As AI systems become more integrated into enterprise environments, the risks extend to what resources the system can access, how it interprets context, and what actions it is allowed to take across connected tools and workflows.

This creates a gap between visibility and control. Prompt security alone allows security teams to observe prompt activity but falls short of creating a clear understanding of how that activity translates into real-world impact across the organization.

Closing that gap requires a broader approach, one that connects signals across human and AI agent identities, SaaS, cloud, and endpoint environments. It means understanding not just how an AI system is being used, but how that usage interacts with the rest of the digital estate.

Prompt security, in that sense, is less of a standalone solution and more of an entry point into a larger problem: securing AI across the enterprise as a whole.

Explore how Darktrace / SECURE AI brings prompt security to enterprises

Darktrace brings more than a decade of AI expertise, built on an enterprise‑wide platform designed to operate in and understand the behaviors of the complex, ambiguous environments where today’s AI now lives. With Darktrace / SECURE AI, enterprises can safely adopt, manage, monitor, and build AI within their business.  

Learn about Darktrace / SECURE AI here.

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Jamie Bali
Technical Author (AI) Developer

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May 20, 2026

State of AI Cybersecurity 2026: 77% of security stacks include AI, but trust is lagging

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Findings in this blog are taken from Darktrace’s annual State of AI Cybersecurity Report 2026.

AI is a contributing member of nearly every modern cybersecurity team. As we discussed earlier in this blog series, rapid AI adoption is expanding the attack surface in ways that security professionals have never before experienced while also empowering attackers to operate at unprecedented speed and scale. It’s only logical that defenders are harnessing the power of AI to fight back.

After all, AI can help cybersecurity teams spot the subtle signs of novel threats before humans can, investigate events more quickly and thoroughly, and automate response. But although AI has been widely adopted, this technology is also frequently misunderstood, and occasionally viewed with suspicion.

For CISOs, the cybersecurity marketplace can be noisy. Making sense of competing vendors’ claims to distinguish the solutions that truly deliver on AI’s full potential from those that do not isn’t always easy. Without a nuanced understanding of the different types of AI used across the cybersecurity stack, it is difficult to make informed decisions about which vendors to work with or how to gain the most value from their solutions. Many security leaders are turning to Managed Security Service Providers (MSSPs) for guidance and support.

The right kinds of AI in the right places?

Back in 2024, when we first conducted this annual survey, more than a quarter of respondents were only vaguely familiar with generative AI or hadn’t heard of it at all. Today, GenAI plays a role in 77% of security stacks. This percentage marks a rapid increase in both awareness and adoption over a relatively short period of time.

According to security professionals, different types of AI are widely integrated into cybersecurity tooling:

  • 67% report that their organization’s security stack uses supervised machine learning
  • 67% report that theirs uses agentic AI
  • 58% report that theirs uses natural language processing (NLP)
  • 35% report that theirs uses unsupervised machine learning

But their responses suggest that organizations aren’t always using the most valuable types of AI for the most relevant use cases.

Despite all the recent attention AI has gotten, supervised machine learning isn’t new. Cybersecurity vendors have been experimenting with models trained on hand-labeled datasets for over a decade. These systems are fed large numbers of examples of malicious activity – for instance, strains of ransomware – and use these examples to generalize common indicators of maliciousness – such as the TTPs of multiple known ransomware strains – so that the models can identify similar attacks in the future. This approach is more effective than signature-based detection, since it isn’t tied to an individual byte sequence or file hash. However, supervised machine learning models can miss patterns or features outside the training data set. When adversarial behavior shifts, these systems can’t easily pivot.

Unsupervised machine learning, by contrast, can identify key patterns and trends in unlabeled data without human input. This enables it to classify information independently and detect anomalies without needing to be taught about past threats. Unsupervised learning can continuously learn about an environment and adapt in real time.

One key distinction between supervised and unsupervised machine learning is that supervised learning algorithms require periodic updating and re-training, whereas unsupervised machine learning trains itself while it works.

The question of trust

Even as AI moves into the mainstream, security professionals are eyeing it with a mix of enthusiasm and caution. Although 89% say they have good visibility into the reasoning behind AI-generated outputs, 74% are limiting AI’s ability to take autonomous action in their SOC until explainability improves. 86% do not allow AI to take even small remediation actions without human oversight.

This model, commonly known as “human in the loop,” is currently the norm across the industry. It seems like a best-of-both-worlds approach that allows teams to experience the benefits of AI-accelerated response without relinquishing control – or needing to trust an AI system.

Keeping humans somewhat in the loop is essential for getting the best out of AI. Analysts will always need to review alerts, make judgement calls, and set guardrails for AI's behavior. Their input helps AI models better understand what “normal” looks like, improving their accuracy over time.

However, relying on human confirmation has real costs – it delays response, increases the cognitive burden analysts must bear, and creates potential coverage gaps when security teams are overwhelmed or unavailable. The traditional model, in which humans monitor and act on every alert, is no longer workable at scale.

If organizations depend too heavily on in-the-loop humans, they risk recreating the very problem AI is meant to solve: backlogs of alerts waiting for analyst review. Removing the human from the loop can buy back valuable time, which analysts can then invest in building a proactive security posture. They can also focus more closely on the most critical incidents, where human attention is truly needed.

Allowing AI to operate autonomously requires trust in its decision-making. This trust can be built gradually over time, with autonomous operations expanding as trust grows. But it also requires knowledge and understanding of AI — what it is, how it works, and how best to deploy it at enterprise scale.

Looking for help in all the right places

To gain access to these capabilities in a way that’s efficient and scalable, growing numbers of security leaders are looking for outsourced support. In fact, 85% of security professionals prefer to obtain new SOC capabilities in the form of a managed service.

This makes sense: Managed Security Service Providers (MSSPs) can deliver deep, continuously available expertise without the cost and complexity of building an in-house team. Outsourcing also allows organizations to scale security coverage up or down as needs change, stay current with evolving threats and regulatory requirements, and leverage AI-native detection and response without needing to manage the AI tools themselves.

Preferences for MSSP-delivered security operations are particularly strong in the education, energy (87%), and healthcare sectors. This makes sense: all are high-value targets for threat actors, and all tend to have limited cybersecurity budgets, so the need for a partner who can deliver affordable access to expertise at scale is strong. Retailers also voiced a strong preference for MSSP-delivered services. These companies are tasked with managing large volumes of consumer personal and financial data, and with transforming an industry traditionally thought of as a late adopter to a vanguard of cyber defense. Technology companies, too, have a marked preference for SOC capabilities delivered by MSSPs. This may simply be because they understand the complexity of the threat landscape – and the advantages of specialized expertise — so well.

In order to help as many organizations as possible – from major enterprises to small and midmarket companies – benefit from enterprise-grade, AI-native security, Darktrace is making it easier for MSSPs to deliver its technology. The ActiveAI Security Portal introduces an alert dashboard designed to increase the speed and efficiency of alert triage, while a new AI-powered managed email security solution is giving MSSPs an edge in the never-ending fight against advanced phishing attacks – helping partners as well as organizations succeed on the frontlines of cyber defense.

Explore the full State of AI Cybersecurity 2026 report for deeper insights into how security leaders are responding to AI-driven risks.

Learn more about securing AI in your enterprise.

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