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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31
Mar 2021
Ransomware: An unwanted present
Darktrace regularly observes an increase in cyber-attacks carried out during holidays, weekends, and outside of working hours. It is clear that such ‘off peak’ attacks allow easy exploitation of standard organizational practices and human vulnerabilities.
As reduced staff wind down and employees mentally and physically log off from the workplace, there is a decline in the speed of detection and triage within an enterprise. This allows threat actors to sneak in unnoticed. Without real-time autonomous systems, when executed these unexpected attacks have a much greater impact on response and recovery.
One of the most frequent threats detected out of hours is ransomware. In 76% of infections, the encryption process begins either after hours or during the weekend. Darktrace was alerted to a ransomware incident which was executed in the early hours of a client’s network on Christmas Day, when most employees were offline.
Figure 1: Timeline of the Christmas Day ransomware breach
Over a week before the encryption began, an initial foothold was established on an unassuming desktop. Using this vector, the threat actor was able to move laterally and gain access to two domain controllers – servers used to verify users and authenticate requests. The two servers then made unusual command and control (C2) connections to a rare endpoint linked to ransomware. Next, the threat went into hiding. Although Darktrace had alerted to this activity at every stage, the security team was under great stress during the December period and did not manage to action even these highly critical alerts. Without Darktrace / NETWORK or Proactive Threat Notifications (PTNs), the threat remained uninterrupted.
It suddenly re-emerged after hours on December 24 and utilized its additional privileges to write suspicious executable files to a range of internal devices. A pre-determined set of company data was exfiltrated and a ransomware payload downloaded from the same cloud destination.
A cyber-attack striking on a public holiday is likely to destabilize communication – who is responsible for dealing with it? Are they hard to reach? Are there different protocols for an out-of-hours breach? When unexpected during the holidays, these questions may be surprisingly hard to answer. When answers finally arrive, it is often too late – the damage has already been done.
Once dealt with, there are also repercussions for evaluation: security personnel will be needed to investigate what happened and the future consequences of the attack. If internal staff are hard to mobilize, and external security services come at a premium, this process can be arduous and key evidence may be lost. In turn, the company will be left open to similar attacks in the future.
Saturday night fearware
Holidays clearly pose a human and logistical vulnerability. However, it is often overlooked that these same down periods occur on a small scale throughout the year – at the end of every week. Darktrace has observed a huge surge in weekend attacks in recent months.
Figure 2: Diagram of the key terms Darktrace has observed over the past six months in out-of-hours model breaches
This includes another ransomware incident, which struck a hospitality organization based in the UK. A company device was compromised when a user unintentionally accessed a harmful email. The infection exploited cleartext password files to laterally move to four other devices, including critical servers which it then used to host outbound spam and further disseminate. For several following weekends, compromised devices made a large volume of open or Tor-hosted C2 connections to endpoints associated with the XINOF ransomware.
This example shows that out-of-hours infections can come from any vector, and human compliance errors can be exploited to quickly propagate malware and hide before the security team returns to work on Monday. With many data breaches already taking months to discover, threat actors are looking to extend their concealment by implementing the initial compromise at times with decreased monitoring.
Improving detection of these first compromises and adapting to smaller out-of-hours periods may lead to improved response and adjustment for larger holidays as well. But for a permanent fix, enterprises need a proactive approach.
The solution which never sleeps
In the case study above, Autonomous Response was possible at every attack stage, had it been switched on in active mode. Darktrace / EMAIL would have stopped the initial compromise by identifying the anomalous attachment and quarantining the infection before it could enter the network. Once inside, the critical servers exploited would not have been compromised, as the malicious login activity using gathered passwords would have been halted until verified. Finally, connections to the malicious sites containing the XINOF payload could have been blocked, stopping further damages from occurring.
Unlike a human, AI never sleeps, and never takes a holiday. Instead, the AI stays active around the clock, containing all types of threats in their earliest stages. This prevents malicious activity from escalating while giving human security teams valuable airtime to react and remediate the root cause of any incidents.
If a security team requires an extra set of eyes to augment their investigation, incidents can also be mitigated with Proactive Threat Notifications (PTNs). This service funnels high-severity detections straight into Darktrace’s customer-dedicated SOC to be investigated by expert cyber analysts. The Darktrace PTN SOC has a follow-the-sun approach to monitoring customer environments, meaning that organizations are protected from attacks around the clock.
Timing is everything
The case studies in this blog should serve as a reminder of the need for 24/7 attentiveness. As security professionals increase their skills and creativity in combating threats, malicious actors continue to adapt themselves and are using timing to their advantage during attacks. Now more than ever, it is clear that autonomous AI-based detection is the only means to remove the advantage of timing from threat actors so that even when the office is closed or the laptop is switched off, your security remains on.
Thanks to Darktrace Product Manager Gabriel Few-Wiegratz for his insights.
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.
Unpacking ClickFix: Darktrace’s detection of a prolific social engineering tactic
ClickFix is a social engineering technique that exploits human error through fake prompts, leading users to unknowingly run malicious commands. Learn how Darktrace detects and responds to such threats!
Darktrace investigated “PumaBot,” a Go-based Linux botnet targeting IoT devices. It avoids internet-wide scanning, instead using a C2 server to get targets and brute-force SSH credentials. Once inside, it executes remote commands and ensures persistence.
Unpacking ClickFix: Darktrace’s detection of a prolific social engineering tactic
What is ClickFix and how does it work?
Amid heightened security awareness, threat actors continue to seek stealthy methods to infiltrate target networks, often finding the human end user to be the most vulnerable and easily exploited entry point.
ClickFix baiting is an exploitation of the end user, making use of social engineering techniques masquerading as error messages or routine verification processes, that can result in malicious code execution.
Since March 2024, the simplicity of this technique has drawn attention from a range of threat actors, from individual cybercriminals to Advanced Persistent Threat (APT) groups such as APT28 and MuddyWater, linked to Russia and Iran respectively, introducing security threats on a broader scale [1]. ClickFix campaigns have been observed affecting organizations in across multiple industries, including healthcare, hospitality, automotive and government [2][3].
Actors carrying out these targeted attacks typically utilize similar techniques, tools and procedures (TTPs) to gain initial access. These include spear phishing attacks, drive-by compromises, or exploiting trust in familiar online platforms, such as GitHub, to deliver malicious payloads [2][3]. Often, a hidden link within an email or malvertisements on compromised legitimate websites redirect the end user to a malicious URL [4]. These take the form of ‘Fix It’ or fake CAPTCHA prompts [4].
From there, users are misled into believing they are completing a human verification step, registering a device, or fixing a non-existent issue such as a webpage display error. As a result, they are guided through a three-step process that ultimately enables the execution of malicious PowerShell commands:
Open a Windows Run dialog box [press Windows Key + R]
Automatically or manually copy and paste a malicious PowerShell command into the terminal [press CTRL+V]
And run the prompt [press ‘Enter’] [2]
Once the malicious PowerShell command is executed, threat actors then establish command and control (C2) communication within the targeted environment before moving laterally through the network with the intent of obtaining and stealing sensitive data [4]. Malicious payloads associated with various malware families, such as XWorm, Lumma, and AsyncRAT, are often deployed [2][3].
Based on investigations conducted by Darktrace’s Threat Research team in early 2025, this blog highlights Darktrace’s capability to detect ClickFix baiting activity following initial access.
Darktrace’s coverage of a ClickFix attack chain
Darktrace identified multiple ClickFix attacks across customer environments in both Europe, the Middle East, and Africa (EMEA) and the United States. The following incident details a specific attack on a customer network that occurred on April 9, 2025.
Although the initial access phase of this specific attack occurred outside Darktrace’s visibility, other affected networks showed compromise beginning with phishing emails or fake CAPTCHA prompts that led users to execute malicious PowerShell commands.
Darktrace’s visibility into the compromise began when the threat actor initiated external communication with their C2 infrastructure, with Darktrace / NETWORK detecting the use of a new PowerShell user agent, indicating an attempt at remote code execution.
Figure 1: Darktrace / NETWORK's detection of a device making an HTTP connection with new PowerShell user agent, indicating PowerShell abuse for C2 communications.
Download of Malicious Files for Lateral Movement
A few minutes later, the compromised device was observed downloading a numerically named file. Numeric files like this are often intentionally nondescript and associated with malware. In this case, the file name adhered to a specific pattern, matching the regular expression: /174(\d){7}/. Further investigation into the file revealed that it contained additional malicious code designed to further exploit remote services and gather device information.
Figure 2: Darktrace / NETWORK's detection of a numeric file, one minute after the new PowerShell User Agent alert.
The file contained a script that sent system information to a specified IP address using an HTTP POST request, which also processed the response. This process was verified through packet capture (PCAP) analysis conducted by the Darktrace Threat Research team.
By analyzing the body content of the HTTP GET request, it was observed that the command converts the current time to Unix epoch time format (i.e., 9 April 2025 13:26:40 GMT), resulting in an additional numeric file observed in the URI: /1744205200.
Figure 3: PCAP highlighting the HTTP GET request that sends information to the specific IP, 193.36.38[.]237, which then generates another numeric file titled per the current time.
Across Darktrace’s investigations into other customers' affected by ClickFix campaigns, both internal information discovery events and further execution of malicious code were observed.
Data Exfiltration
By following the HTTP stream in the same PCAP, the Darktrace Threat Research Team assessed the activity as indicative of data exfiltration involving system and device information to the same command-and-control (C2) endpoint, , 193.36.38[.]237. This endpoint was flagged as malicious by multiple open-source intelligence (OSINT) vendors [5].
Figure 4: PCAP highlighting HTTP POST connection with the numeric file per the URI /1744205200 that indicates data exfiltration to 193.36.38[.]237.
Further analysis of Darktrace’s Advanced Search logs showed that the attacker’s malicious code scanned for internal system information, which was then sent to a C2 server via an HTTP POST request, indicating data exfiltration
Figure 5: Advanced Search further highlights Darktrace's observation of the HTTP POST request, with the second numeric file representing data exfiltration.
Actions on objectives
Around ten minutes after the initial C2 communications, the compromised device was observed connecting to an additional rare endpoint, 188.34.195[.]44. Further analysis of this endpoint confirmed its association with ClickFix campaigns, with several OSINT vendors linking it to previously reported attacks [6].
In the final HTTP POST request made by the device, Darktrace detected a file at the URI /init1234 in the connection logs to the malicious endpoint 188.34.195[.]44, likely depicting the successful completion of the attack’s objective, automated data egress to a ClickFix C2 server.
Darktrace / NETWORK grouped together the observed indicators of compromise (IoCs) on the compromised device and triggered an Enhanced Monitoring model alert, a high-priority detection model designed to identify activity indicative of the early stages of an attack. These models are monitored and triaged 24/7 by Darktrace’s Security Operations Center (SOC) as part of the Managed Threat Detection service, ensuring customers are promptly notified of malicious activity as soon as it emerges.
Figure 6: Darktrace correlated the separate malicious connections that pertained to a single campaign.
Darktrace Autonomous Response
In the incident outlined above, Darktrace was not configured in Autonomous Response mode. As a result, while actions to block specific connections were suggested, they had to be manually implemented by the customer’s security team. Due to the speed of the attack, this need for manual intervention allowed the threat to escalate without interruption.
However, in a different example, Autonomous Response was fully enabled, allowing Darktrace to immediately block connections to the malicious endpoint (138.199.156[.]22) just one second after the initial connection in which a numerically named file was downloaded [7].
Figure 7: Darktrace Autonomous Response blocked connections to a suspicious endpoint following the observation of the numeric file download.
This customer was also subscribed to our Managed Detection and Response service, Darktrace’s SOC extended a ‘Quarantine Device’ action that had already been autonomously applied in order to buy their security team additional time for remediation.
Figure 8: Autonomous Response blocked connections to malicious endpoints, including 138.199.156[.]22, 185.250.151[.]155, and rkuagqnmnypetvf[.]top, and also quarantined the affected device. These actions were later manually reinforced by the Darktrace SOC.
Conclusion
ClickFix baiting is a widely used tactic in which threat actors exploit human error to bypass security defenses. By tricking end point users into performing seemingly harmless, everyday actions, attackers gain initial access to systems where they can access and exfiltrate sensitive data.
Darktrace’s anomaly-based approach to threat detection identifies early indicators of targeted attacks without relying on prior knowledge or IoCs. By continuously learning each device’s unique pattern of life, Darktrace detects subtle deviations that may signal a compromise. In this case, Darktrace's Autonomous Response, when operating in a fully autonomous mode, was able to swiftly contain the threat before it could progress further along the attack lifecycle.
Credit to Keanna Grelicha (Cyber Analyst) and Jennifer Beckett (Cyber Analyst)
Appendices
NETWORK Models
Device / New PowerShell User Agent
Anomalous Connection / New User Agent to IP Without Hostname
Anomalous Connection / Posting HTTP to IP Without Hostname
Anomalous Connection / Powershell to Rare External
Device / Suspicious Domain
Device / New User Agent and New IP
Anomalous File / New User Agent Followed By Numeric File Download (Enhanced Monitoring Model)
Security teams are drowning in vulnerability alerts, but only a fraction of those issues pose a real threat. The new Exploit Prediction Assessment feature in Darktrace / Attack Surface Management helps teams cut through the noise by validating which vulnerabilities on their external attack surface can be actively exploited.
Instead of relying solely on CVSS scores or waiting for patch cycles, Exploit Prediction Assessment uses safe, targeted simulations to test whether exposed systems can be compromised, delivering fast, evidence-based results in under 72 hours.
This capability augments traditional pen testing and complements existing ASM workflows by transforming passive discovery into actionable insight. With EPA, security teams move from reacting to long lists of potential vulnerabilities to making confident, risk-based decisions on what actually matters.
Key highlights of Exploit Prediction Assessment
Simulated attacks to validate real risk
Exploit Prediction Assessment conducts safe, simulated attacks on assets with potential security vulnerabilities that have been identified by Darktrace / Attack Surface Management. This real-time testing validates your systems' susceptibility to compromise by confirming which vulnerabilities are present and exploitable on your attack surface.
Prioritize what matters most
Confirmed security risks can be prioritized for mitigation, ensuring that the most critical threats are promptly addressed. This takes the existing letter ranking system and brings it a step further by drilling down to yet another level. Even in the most overwhelming situations, teams will be able to act on a pragmatic, clear-cut plan.
Fast results, tailored to your environment
Customers set the scope of the Exploit Prediction Assessment within Darktrace / Attack Surface Management and receive the results of the surgical vulnerability testing within 72 hours. Users will see 1 of 2 shields:
1. A green shield with a check mark: Meaning no vulnerabilities were found on scanned CVEs for the asset.
2. A red shield with a red x: Meaning at least one vulnerability was found on scanned CVEs for the asset.
Why it's a game changer
Traditionally, attack surface management tools have focused on identifying exposed assets and vulnerabilities but lacked the context to determine which issues posed the greatest risk. Without context on what’s exploitable, security teams are left triaging long lists of potential risks, operating in isolation from broader business objectives. This misalignment ultimately leads to both weakened risk posture and cross team communication and execution.
This is where Continuous Threat Exposure Management (CTEM) becomes essential. Introduced by Gartner, CTEM is a framework that helps organizations continuously assess, validate, and improve their exposure to real-world threats. The goal isn’t just visibility, it’s to understand how an attacker could move through your environment today, and what to fix first to stop them.
Exploit Prediction Assessment brings this philosophy to life within Darktrace / Attack Surface Management. By safely simulating exploit attempts against identified vulnerabilities, it validates which exposures are truly at risk—transforming ASM from a discovery tool into a risk-based decision engine.
This capability directly supports the validation and prioritization phases of CTEM, helping teams focus on exploitable vulnerabilities rather than theoretical ones. This shift from visibility to action reduces the risk of critical vulnerabilities in the technology stack being overlooked, turning overwhelming vulnerability data into focused, clear actionable insights.
As attack surfaces continue to grow and change, organizations need more than static scans they need continuous, contextual insight. Exploit Prediction Assessment ensures your ASM efforts evolve with the threat landscape, making CTEM a practical reality, not just a strategy.
Exploit Prediction Assessment in action
With Darktrace / Attack Surface Management organizations can get Exploit Prediction Assessment, and the cyber risk team no longer guesses which vulnerabilities matter most. Instead, they identify several externally exposed areas of their attack surface, then use the feature to surgically test for exploitability across these exposed endpoints. Within 72 hours, they receive a report:
Positive outcome: Based on information in the html or the headers it seems that a vulnerable software version is running on an externally exposed infrastructure. By running a targeted attack on this infrastructure, we can confirm that it cannot be abused.
Negative outcome: Based on information in the html or the headers it seems that a vulnerable software version is running on an externally exposed infrastructure. By running a targeted attack on this infrastructure, we can confirm that it can be exploited, so we can predict it being exploited.
This second outcome changes everything. The team immediately prioritizes the exploitable asset for patching and takes the necessary adjustments to mitigate exposure until the fix is deployed.
Instead of spreading their resources thin across dozens of alerts, they focus on what poses a real threat, saving time, reducing risk, and demonstrating actionable results to stakeholders.
Conclusion
Exploit Predication Assessment bolsters Darktrace’s commitment to proactive cybersecurity. It supports intelligent prioritization of vulnerabilities, keeping organizations ahead of emerging threats. With this new addition to / Attack Surface Management, teams have another tool to empower a more efficient approach to addressing security gaps in real-time.
Stay tuned for more updates and insights on how Darktrace continues to develop a culture of proactive security across the entire ActiveAI Security Platform.
![PCAP highlighting the HTTP GET request that sends information to the specific IP, 193.36.38[.]237, which then generates another numeric file titled per the current time.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/684068fac1b4368f672c17cc_Screenshot%202025-06-04%20at%208.40.32%E2%80%AFAM.png)
![PCAP highlighting HTTP POST connection with the numeric file per the URI /1744205200 that indicates data exfiltration to 193.36.38[.]237.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/6840694509d92b6220ccf5f1_Screenshot%202025-06-04%20at%208.41.48%E2%80%AFAM.png)
![Autonomous Response blocked connections to malicious endpoints, including 138.199.156[.]22, 185.250.151[.]155, and rkuagqnmnypetvf[.]top, and also quarantined the affected device. These actions were later manually reinforced by the Darktrace SOC.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/68406a1f723c9d6fda9c5268_Screenshot%202025-06-04%20at%208.45.23%E2%80%AFAM.png)
