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October 11, 2017

Stealth Attacks: The ‘Matrix Banker’ Reloaded

Over the last few weeks, Darktrace has confidently identified traces of the resurgence of a stealthy attack targeting Latin American companies. Learn more!
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
Max Heinemeyer
Global Field CISO
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11
Oct 2017

Overview

Over the last few weeks, Darktrace has confidently identified traces of the resurgence of a stealthy attack targeting Latin American companies. This targeted campaign was first observed between March and June this year. Arbor Networks initially labelled the malware used in the campaign ‘Matrix Banker’. The name used by Proofpoint is ‘Win32/RediModiUpd’. The malware used by the attackers appeared to be still under development when the last report came out in June 2017.

Darktrace has observed an attack wave targeting Mexican companies in August and September 2017. Some of the TTPs (tools, techniques, procedures) observed bear close resemblance to those seen in the ‘Matrix Banker’ attacks earlier this year. The campaign is crafted to be particularly stealthy and to blend into certain networks in Latin America, confirming the suspicion of its targeted nature. Darktrace’s machine learning and AI algorithms were able to identify the infected devices almost instantaneously, despite apparent efforts by the malware author to be covert and stealthy.

Between August and October 2017, Darktrace detected highly anomalous behavior on five seemingly unrelated networks in Mexico. Unlike the original strain of this attack, which was believed to target financial institutions almost exclusively, this latest variant affected customers across a number of industry verticals, suggesting that the threat actors are diversifying their targets. Darktrace has seen the attack hit companies in the healthcare, telecommunications, food and retail sectors.

Infection process

The initial infection vector appears to be phishing emails. The users downloaded the initial piece of malware from compromised Mexican websites. The infected files were Windows executables masqueraded as .mp3 and .gif files. Example downloads are listed below. Darktrace instantly detected the highly anomalous behavior of these downloads, which occurred from 100% rare external domains for the networks, and alerted the respective security teams.

hxxp://gorrasbaratas.com[.]mx/images/sss/sound.mp3 [1]
hxxp://inseltech.com[.]mx/inicio/wp-includes/kk/sound.mp3 [2]

The actual file names of the downloads are ‘logo.gif’.

The ‘Matrix Bankers’ attack tried to conceal malware downloads using masqueraded files in previous attacks. What is interesting about the hacked websites serving the malware is that they are using the .mx top level domain. This localised and targeted technique is used to conceal the traffic and make it blend in with normal network traffic on networks in Mexico.

Following the initial infection, in some cases a second stage malware was downloaded. Darktrace detected this as more anomalous activity since the downloads took place from more 100% rare external destinations:

hxxp://dackdack[.]club/APIv3/modules/nn_grabber_x64.dll [3]
hxxp://dackdack[.]club/APIv3/modules/nn_grabber_x32.dll [4]

Successful second stage downloads were seen to be followed by suspicious HTTP POST beaconing behavior, resembling command and control communication to various domains:

hxxp://kuxkux[.]bit/APIv3/api.php
hxxp://drdrfdd[.]cat/forum/logout.php
hxxp://eaxsess[.]cat/forum/logout.php

Not all targeted companies were seen to receive a second-stage malware download. This might indicate a sophisticated attack plan where the initial generic, covert backdoor is followed by a targeted second-stage payload that is chosen based on the victim and its potential value to the cyber criminals (long term data exfiltration, ransomware, banking Trojan…). Customers reported that infected devices had their anti-virus disabled, or removed by the malware. This showcases that companies cannot solely rely on signature based systems to catch novel, evolving threats.

The beaconing behavior to these 100% unusual external domains was immediately detected as it represented a strong deviation from the devices’ normal ‘pattern of life’. The use of domains hosted on .cat (top level domain used for the Catalan culture and language) indicates that the attackers are highly aware of the cultural context of their target victims and try to make the malware communication blend in with network traffic.

Compromised machines made further repeated DNS requests to the domains below:

dackdack[.]tech
dackdack[.]online
kuykuy[.]bit

At the time of our investigation, the domains below resolved to the following IP address:

142.44.188[.]42
dackdack[.]club
eaxsess[.]cat
kuxkux[.]bit
drdrfdd[.]cat

Closing thoughts

Although final attribution is impossible, the evidence strongly suggests that the campaign described here is similar to the ‘Matrix Banker’ campaign observed in March and June 2017 and might be a continuation of it.

The initial malware was concealing its file types by using different file extensions than their MIME type. More precisely, the use of ‘logo.gif’ has been seen in previous ‘Matrix Banker’ attacks.

There are 3,000 deployments of Darktrace’s AI technology across 70 countries, but all identified instances of this type of compromise are in Latin American organizations.

The ‘Matrix Bankers’ have used Catalan top-level domains in past attacks. In fact, some of the domains used previously are very similar to domains observed here. One domain seen in September was the exact same domain as seen in an earlier attack – just with an additional ‘s’ appended:

Example domains from March/June 2017

trtr44[.]cat
lalax[.]cat
eaxses[.]cat

Example domains from August/October 2017

drdrfdd[.]cat
kuxkux[.]bit
eaxsess[.]cat
kuykuy[.]bit
dackdack[.]tech

Although the domains appear to be randomly generated, a closer look reveals that the ‘Matrix Bankers’ seem to favor generating domain names by using keys that are physically close together on a keyboard, or by repeating phrases one might type in a hurry, when lacking creativity for naming a temporary download (e.g. asdasd.jpeg). We saw this pattern for domain name generation in the March - June ‘Matrix Bankers’ campaign as well as here.

Darktrace’s AI technology was able to detect these stealthy and sophisticated attacks because the way in which they manifest themselves represents a sharp deviation from the normal ‘pattern of life’ within an organization. The threat actors applied a number of techniques to blend into the normal noise of networks, but the self-learning algorithms were quick in detecting the anomalous behavior automatically and in real time.

Footnotes

List of IoCs

dackdack[.]club
dackdack[.]tech
dackdack[.]online
eaxsess[.]cat
kuxkux[.]bit
kuykuy[.]bit
drdrfdd[.]cat
inseltech.com[.]mx
gorrasbaratas.com[.]mx
142.44.188[.]42

[1] VirusTotal analysis of this file
[2] SHA-1: 88f3bdc84908c1fb844b337c535eef2d2b31e1dc
[3] VirusTotal analysis of this file
[4] VirusTotal analysis of this file

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
Max Heinemeyer
Global Field CISO

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April 2, 2026

How Chinese-Nexus Cyber Operations Have Evolved – And What It Means For Cyber Risk and Resilience 

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Cybersecurity has traditionally organized risk around incidents, breaches, campaigns, and threat groups. Those elements still matter—but if we fixate on individual incidents, we risk missing the shaping of the entire ecosystem. Nation‑state–aligned operators are increasingly using cyber operations to establish long-term strategic leverage, not just to execute isolated attacks or short‑term objectives.  

Our latest research, Crimson Echo, shifts the lens accordingly. Instead of dissecting campaigns, malware families, or actor labels as discrete events, the threat research team analyzed Chinese‑nexus activity as a continuum of behaviors over time. That broader view reveals how these operators position themselves within environments: quietly, patiently, and persistently—often preparing the ground long before any recognizable “incident” occurs.  

How Chinese-nexus cyber threats have changed over time

Chinese-nexus cyber activity has evolved in four phases over the past two decades. This ranges from early, high-volume operations in the 1990s and early 2000s to more structured, strategically-aligned activity in the 2010s, and now toward highly adaptive, identity-centric intrusions.  

Today’s phase is defined by scale, operational restraint, and persistence. Attackers are establishing access, evaluating its strategic value, and maintaining it over time. This reflects a broader shift: cyber operations are increasingly integrated into long-term economic and geopolitical strategies. Access to digital environments, specifically those tied to critical national infrastructure, supply chains, and advanced technology, has become a form of strategic leverage for the long-term.  

How Darktrace analysts took a behavioral approach to a complex problem

One of the challenges in analyzing nation-state cyber activity is attribution. Traditional approaches often rely on tracking specific threat groups, malware families, or infrastructure. But these change constantly, and in the case of Chinese-nexus operations, they often overlap.

Crimson Echo is the result of a retrospective analysis of three years of anomalous activity observed across the Darktrace fleet between July 2022 and September 2025. Using behavioral detection, threat hunting, open-source intelligence, and a structured attribution framework (the Darktrace Cybersecurity Attribution Framework), the team identified dozens of medium- to high-confidence cases and analyzed them for recurring operational patterns.  

This long-horizon, behavior-centric approach allows Darktrace to identify consistent patterns in how intrusions unfold, reinforcing that behavioral patterns that matter.  

What the data shows

Several clear trends emerged from the analysis:

  • Targeting is concentrated in strategically important sectors. Across the dataset, 88% of intrusions occurred in organizations classified as critical infrastructure, including transportation, critical manufacturing, telecommunications, government, healthcare, and Information Technology (IT) services.  
  • Strategically important Western economies are a primary focus. The US alone accounted for 22.5% of observed cases, and when combined with major European economies including Germany, Italy, Spain and the UK, over half of all intrusions (55%) were concentrated in these regions.  
  • Nearly 63% of intrusions of intrusions began with the exploitation of internet-facing systems, reinforcing the continued risk posed by externally exposed infrastructure.  

Two models of cyber operations

Across the dataset, Chinese-nexus activity followed two operational models.  

The first is best described as “smash and grab.” These are short-horizon intrusions optimized for speed. Attackers move quickly – often exfiltrating data within 48 hours – and prioritize scale over stealth. The median duration of these compromises is around 10 days. It’s clear they are willing to risk detection for short-term gain.  

The second is “low and slow.” These operations were less prevalent in the dataset, but potentially more consequential. Here, attackers prioritize persistence, establishing durable access through identity systems and legitimate administrative tools, so they can maintain access undetected for months or even years. In one notable case, the actor had fully compromised the environment and established persistence, only to resurface in the environment more than 600 days after. The operational pause underscores both the depth of the intrusion and the actor’s long‑term strategic intent. This suggests that cyber access is a strategic asset to preserve and leverage over time, and we observed these attacks most often inin sectors of the high strategic importance.  

It’s important to note that the same operational ecosystem can employ both models concurrently, selecting the appropriate model based on target value, urgency, intended access. The observation of a “smash and grab” model should not be solely interpreted as a failure of tradecraft, but instead an operational choice likely aligned with objectives. Where “low and slow” operations are optimized for patience, smash and grab is optimized for speed; both seemingly are deliberate operational choices, not necessarily indicators of capability.  

Rethinking cyber risk

For many organizations, cyber risk is still framed as a series of discrete events. Something happens, it is detected and contained, and the organization moves on. But persistent access, particularly in deeply interconnected environments that span cloud, identity-based SaaS and agentic systems, and complex supply chain networks, creates a major ongoing exposure risk. Even in the absence of disruption or data theft, that access can provide insight into operations, dependencies, and strategic decision-making. Cyber risk increasingly resembles long-term competitive intelligence.  

This has impact beyond the Security Operations Center. Organizations need to shift how they think about governance, visibility, and resilience, and treat cyber exposure as a structural business risk instead of an incident response challenge.  

What comes next

The goal of this research is to provide a clearer understanding of how these operations work, so defenders can recognize them earlier and respond more effectively. That includes shifting from tracking indicators to understanding behaviors, treating identity providers as critical infrastructure risks, expanding supplier oversight, investing in rapid containment capabilities, and more.  

Learn more about the findings of Darktrace’s latest research, Crimson Echo: Understanding Chinese-nexus Cyber Operations Through Behavioral Analysis, by downloading the full report and summaries for business leaders, CISOs, and SOC analysts here.  

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About the author
Nathaniel Jones
VP, Security & AI Strategy, Field CISO

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April 1, 2026

AI-powered security for a rapidly growing grocery enterprise

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Protecting a complex, fast-growing retail organization

For this multi-banner grocery holding organization, cybersecurity is considered an essential business enabler, protecting operations, growth, and customer trust. The organization’s lean IT team manages a highly distributed environment spanning corporate offices, 100+ stores, distribution centers and  thousands of endpoints, users, and third-party connections.

Mergers and acquisitions fueled rapid growth, but they also introduced escalating complexity that constrained visibility into users, endpoints, and security risks inherited across acquired environments.

Closing critical visibility gaps with limited resources

Enterprise-wide visibility is a top priority for the organization, says the  Vice President of Information Technology. “We needed insights beyond the perimeter into how users and devices were behaving across the organization.”

A security breach that occurred before the current IT leadership joined the company reinforced the urgency and elevated cybersecurity to an executive-level priority with a focus on protecting customer trust. The goal was to build a multi-layered security model that could deliver autonomous, enterprise-wide protection without adding headcount.

Managing cyber risk in M&A

Mergers and acquisitions are central to the grocery holding company’s growth strategy. But each transaction introduces new cyber risk, including inherited network architectures, inconsistent tooling, excessive privileges, and remnants of prior security incidents that were never fully remediated.

“Our M&A targets range from small chains with a single IT person and limited cyber tools to large chains with more developed IT teams, toolsets and instrumentation,” explains the VP of IT. “We needed a fast, repeatable, and reliable way to assess cyber risk before transactions closed.”

AI-driven security built for scale, speed, and resilience

Rather than layering additional point tools onto an already complex environment, the retailer adopted the Darktrace ActiveAI Security Platform™ in 2020 as part of a broader modernization effort to improve resilience, close visibility gaps, and establish a security foundation that could scale with growth.

“Darktrace’s AI-driven approach provided the ideal solution to these challenges,” shares the VP of IT. “It has empowered our organization to maintain a robust security strategy, ensuring the protection of our network and the smooth operation of our business.”

Enterprise-wide visibility into traffic  

By monitoring both north-south and east-west traffic and applying Self-Learning AI, Darktrace develops a dynamic understanding of how users and devices normally behave across locations, roles, and systems.

“Modeling normal behavior across the environment enables us to quickly spot behavior that doesn’t fit. Even subtle changes that could signal a threat but appear legitimate at first glance,” explains the VP of IT.

Real-time threat containment, 24/7

Adopting autonomous response has created operational breathing room for the security team, says the company’s Cybersecurity  Engineer.

“Early on, we enabled full Darktrace autonomous mode and we continue to do so today,” shares the IT Security Architect. “Allowing the technology to act first gives us the time we need to investigate incidents during business hours without putting the business at risk.”

Unified, actionable view of security ecosystem

The grocery retailer integrated Darktrace with its existing security ecosystem of firewalls, vulnerability management tools, and endpoint detection and response, and the VP of IT described the adoption process as “exceptionally smooth.”

The team can correlate enterprise-wide security data for a unified and actionable picture of all activity and risk. Using this “single pane of glass” approach, the retailer trains Level 1 and Level 2 operations staff to assist with investigations and user follow-ups, effectively extending the reach of the security function without expanding headcount.

From reactive defense to security at scale

With Darktrace delivering continuous visibility, autonomous containment, and integrated security workflows, the organization has strengthened its cybersecurity posture while improving operational efficiency. The result is a security model that not only reduces risk, but also supports growth, resilience, and informed decision-making at the business level.

Faster detection, faster resolution

With autonomous detection and response, the retailer can immediately contain risk while analysts investigate and validate activity. With this approach, the company can maintain continuous protection even outside business hours and reduce the chance of lateral spread across systems or locations.

Enterprise-grade protection with a lean team

From cloud environments to clients to SaaS collaboration tools, Darktrace provides holistic autonomous AI defense, processing petabytes of the organization’s network traffic and investigating millions of individual events that could be indicative of a wider incident.

Today, Darktrace autonomously conducts the majority of all investigations on behalf of the IT team, escalating only a tiny fraction for analyst review. The impact has been profound, freeing analysts from endless alerts and hours of triage so they can focus on more valuable, proactive, and gratifying work.

“From an operational perspective, Darktrace gives us time back,” says the Cybersecurity Engineer. More importantly, says the VP of IT, “it gives us peace of mind that we’re protected even if we’re not actively monitoring every alert.”

A strategic input for M&A decision-making

One of the most strategic outcomes has been the role of cybersecurity on M&A. 90 days prior to closing a transaction, the security team uses Darktrace alongside other tools to perform a cyber risk assessment of the potential acquisition. “Our approach with Darktrace has consistently identified gaps and exposed risks,” says the VP of IT, including:

  • Remnants of previous incidents that were never fully remediated
  • Network configurations with direct internet exposure
  • Excessive administrative privileges in Active Directory or on critical hosts

While security findings may not alter deal timelines, the VP of IT says they can have enormous business implications. “With early visibility into these risks, we can reduce exposure to inherited cyber threats, strengthen our position during negotiations, and establish clear remediation requirements.”

A security strategy built to evolve with the business

As the holding group expands its cloud footprint, it will extend Darktrace protections into Azure, applying the same AI-driven visibility and autonomous response to cloud workloads. The VP of IT says Darktrace's evolving capabilities will be instrumental in addressing the organization’s future cybersecurity needs and ability to adapt to the dynamic nature of cloud security.

“With Darktrace’s AI-driven approach, we have moved beyond reactive defense, establishing a resilient security foundation for confident expansion and modernization.”

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