Protect your business from QuickBooks impersonation phishing attacks with Darktrace Email and learn how to defend against cyber threats.
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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.
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23
Jun 2020
Recently in the Darktrace Blog we’ve explored how the current working conditions have resulted in a huge surge in spoofing and impersonation attacks, where attackers masquerade either as trusted colleagues or familiar brands.
These types of email attacks continue to be a successful tactic for cyber-criminals. Forever responsive and adaptive, attackers are taking advantage of the disruption to everyday operations by impersonating credible suppliers to send in fake invoices and other fraudulent emails.
How AI caught a fake invoice attack
This blog explores a string of counterfeit invoices sent to dozens of employees at a cutting-edge technology company. With valuable IP and several research labs, the company is a prime target for organized and ambitious cyber-criminals seeking maximum financial reward for their campaigns. In this particular incident, the threat-actors convincingly impersonated QuickBooks, a leading provider of book-keeping and accounting software, and part of the Intuit group which includes other recognizable brands like TurboTax and Mint.
The spoofed emails contained an invoice notification that closely imitated a legitimate monthly invoice that the organization would expect to receive from QuickBooks. If successfully delivered to the inbox, these would have appeared to come from quickbooks@notification.intuit[.]com.
The ‘invoice’ attached to these emails was actually a macro-containing Office document.
Figure 1: The malicious attachment shown in the Threat Visualizer
The source of the spoofed emails was an IP address in Italy. Since this falls outside the range of IPs that are permitted by Intuit to send mail on their behalf, this breached the SPF model breach within Antigena Email.
However, that in itself was not the main cause for Darktrace/Email’s detection – any mail server can run an SPF check. The primary factor behind the 100% anomaly score that Darktrace/Email assigned these emails was the high sender history of the email address – Darktrace was able to see that the failed SPF results were particularly suspicious against the background of SPF passes usually assigned to quickbooks@notification.intuit[.]com.
In addition, Darktrace/Email recognized that it would be highly unusual for this group of recipients, across multiple departments, to be receiving the same email from the same source – particularly of that particular subject matter. This caused the Cyber AI to hold the emails back in some cases, and in others it took the action to ‘unspoof’ the email, revealing that the invoice was not in fact from Quickbooks.
Figure 2: Five of the offending emails, deemed 100% anomalous by Darktrace/Email
The above illustrates how these emails appeared in Darktrace’s Threat Visualizer, in comparison to normal legitimate invoices below. Note the identical sender address and similar style of subject line. Had Darktrace’s AI not been analyzing every inbound email in real time, these attacks would have been highly likely to succeed.
Figure 3: Genuine invoices received from Intuit in the same week
The below is a full list of the model breaches piled onto these emails, producing the overall anomaly score of 100% seen above.
Attachment/Dangerous AttachmentAttachment/SPF Anomalous AttachmentAttachment/Spoof Sender AttachmentAttachment/Unsolicited AttachmentSpoof/Meta Popular Domain SpoofType/High Sender HistoryUnusual/Behavioral AnomalyUnusual/Connection AnomaliesValidation/SPF AnomalousValidation/SPF Fail Known Correspondent
Catching the full range of email attacks
Thankfully, the organization in question was an early adopter of a Self-Learning, AI-powered approach to email security, and the attack was contained at an early stage. But this attack is nothing extraordinary – and these kind of impersonation attempts are affecting organizations across every industry on a daily basis.
The extension of the tax season in the US this year has brought with it a widened opportunity for cyber-criminals to exploit the flurry of activity with fake invoices and other similar attacks. Predictably, a second surge of attacks targeting individuals and small businesses has been reported.
We have already seen an increase of COVID-19 related email attacks. With attackers impersonating trusted brands like Intuit’s TurboTax and QuickBooks, the necessity for defenders to adopt Cyber AI as part of their email security defense is more prevalent than ever.
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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.
Patch and Persist: Darktrace’s Detection of Blind Eagle (APT-C-36)
What is Blind Eagle?
Since 2018, APT-C-36, also known as Blind Eagle, has been observed performing cyber-attacks targeting various sectors across multiple countries in Latin America, with a particular focus on Colombian organizations.
Blind Eagle characteristically targets government institutions, financial organizations, and critical infrastructure [1][2].
Attacks carried out by Blind Eagle actors typically start with a phishing email and the group have been observed utilizing various Remote Access Trojans (RAT) variants, which often have in-built methods for hiding command-and-control (C2) traffic from detection [3].
What we know about Blind Eagle from a recent campaign
Since November 2024, Blind Eagle actors have been conducting an ongoing campaign targeting Colombian organizations [1].
In this campaign, threat actors have been observed using phishing emails to deliver malicious URL links to targeted recipients, similar to the way threat actors have previously been observed exploiting CVE-2024-43451, a vulnerability in Microsoft Windows that allows the disclosure of a user’s NTLMv2 password hash upon minimal interaction with a malicious file [4].
Despite Microsoft patching this vulnerability in November 2024 [1][4], Blind Eagle actors have continued to exploit the minimal interaction mechanism, though no longer with the intent of harvesting NTLMv2 password hashes. Instead, phishing emails are sent to targets containing a malicious URL which, when clicked, initiates the download of a malicious file. This file is then triggered by minimal user interaction.
Clicking on the file triggers a WebDAV request, with a connection being made over HTTP port 80 using the user agent ‘Microsoft-WebDAV-MiniRedir/10.0.19044’. WebDAV is a transmission protocol which allows files or complete directories to be made available through the internet, and to be transmitted to devices [5]. The next stage payload is then downloaded via another WebDAV request and malware is executed on the target device.
Attackers are notified when a recipient downloads the malicious files they send, providing an insight into potential targets [1].
Darktrace’s coverage of Blind Eagle
In late February 2025, Darktrace observed activity assessed with medium confidence to be associated with Blind Eagle on the network of a customer in Colombia.
Within a period of just five hours, Darktrace / NETWORK detected a device being redirected through a rare external location, downloading multiple executable files, and ultimately exfiltrating data from the customer’s environment.
Since the customer did not have Darktrace’s Autonomous Response capability enabled on their network, no actions were taken to contain the compromise, allowing it to escalate until the customer’s security team responded to the alerts provided by Darktrace.
Darktrace observed a device on the customer’s network being directed over HTTP to a rare external IP, namely 62[.]60[.]226[.]112, which had never previously been seen in this customer’s environment and was geolocated in Germany. Multiple open-source intelligence (OSINT) providers have since linked this endpoint with phishing and malware campaigns [9].
The device then proceeded to download the executable file hxxp://62[.]60[.]226[.]112/file/3601_2042.exe.
Figure 1: Darktrace’s detection of the affected device connecting to an unusual location based in Germany.
Figure 2: Darktrace’s detection of the affected device downloading an executable file from the suspicious endpoint.
The device was then observed making unusual connections to the rare endpoint 21ene.ip-ddns[.]com and performing unusual external data activity.
This dynamic DNS endpoint allows a device to access an endpoint using a domain name in place of a changing IP address. Dynamic DNS services ensure the DNS record of a domain name is automatically updated when the IP address changes. As such, malicious actors can use these services and endpoints to dynamically establish connections to C2 infrastructure [6].
Further investigation into this dynamic endpoint using OSINT revealed multiple associations with previous likely Blind Eagle compromises, as well as Remcos malware, a RAT commonly deployed via phishing campaigns [7][8][10].
Figure 3: Darktrace’s detection of the affected device connecting to the suspicious dynamic DNS endpoint, 21ene.ip-ddns[.]com.
Shortly after this, Darktrace observed the user agent ‘Microsoft-WebDAV-MiniRedir/10.0.19045’, indicating usage of the aforementioned transmission protocol WebDAV. The device was subsequently observed connected to an endpoint associated with Github and downloading data, suggesting that the device was retrieving a malicious tool or payload. The device then began to communicate to the malicious endpoint diciembrenotasenclub[.]longmusic[.]com over the new TCP port 1512 [11].
Around this time, the device was also observed uploading data to the endpoints 21ene.ip-ddns[.]com and diciembrenotasenclub[.]longmusic[.]com, with transfers of 60 MiB and 5.6 MiB observed respectively.
Figure 4: UI graph showing external data transfer activity.
This chain of activity triggered an Enhanced Monitoring model alert in Darktrace / NETWORK. These high-priority model alerts are designed to trigger in response to higher fidelity indicators of compromise (IoCs), suggesting that a device is performing activity consistent with a compromise.
Figure 5: Darktrace’s detection of initial attack chain activity.
A second Enhanced Monitoring model was also triggered by this device following the download of the aforementioned executable file (hxxp://62[.]60[.]226[.]112/file/3601_2042.exe) and the observed increase in C2 activity.
Following this activity, Darktrace continued to observe the device beaconing to the 21ene.ip-ddns[.]com endpoint.
Darktrace’s Cyber AI Analyst was able to correlate each of the individual detections involved in this compromise, identifying them as part of a broader incident that encompassed C2 connectivity, suspicious downloads, and external data transfers.
Figure 6: Cyber AI Analyst’s investigation into the activity observed on the affected device.
Figure 7: Cyber AI Analyst’s detection of the affected device’s broader connectivity throughout the course of the attack.
As the affected customer did not have Darktrace’s Autonomous Response configured at the time, the attack was able to progress unabated. Had Darktrace been properly enabled, it would have been able to take a number of actions to halt the escalation of the attack.
For example, the unusual beaconing connections and the download of an unexpected file from an uncommon location would have been shut down by blocking the device from making external connections to the relevant destinations.
Conclusion
The persistence of Blind Eagle and ability to adapt its tactics, even after patches were released, and the speed at which the group were able to continue using pre-established TTPs highlights that timely vulnerability management and patch application, while essential, is not a standalone defense.
Organizations must adopt security solutions that use anomaly-based detection to identify emerging and adapting threats by recognizing deviations in user or device behavior that may indicate malicious activity. Complementing this with an autonomous decision maker that can identify, connect, and contain compromise-like activity is crucial for safeguarding organizational networks against constantly evolving and sophisticated threat actors.
Credit to Charlotte Thompson (Senior Cyber Analyst), Eugene Chua (Principal Cyber Analyst) and Ryan Traill (Analyst Content Lead)
Appendices
IoCs
IoC – Type - Confidence Microsoft-WebDAV-MiniRedir/10.0.19045 – User Agent
62[.]60[.]226[.]112 – IP – Medium Confidence
hxxp://62[.]60[.]226[.]112/file/3601_2042.exe – Payload Download – Medium Confidence
21ene.ip-ddns[.]com – Dynamic DNS Endpoint – Medium Confidence
diciembrenotasenclub[.]longmusic[.]com - Hostname – Medium Confidence
Darktrace’s model alert coverage
Anomalous File / Suspicious HTTP Redirect Anomalous File / EXE from Rare External Location Anomalous File / Multiple EXE from Rare External Location Anomalous Server Activity / Outgoing from Server Unusual Activity / Unusual External Data to New Endpoint Device / Anomalous Github Download Anomalous Connection / Multiple Connections to New External TCP Port Device / Initial Attack Chain Activity Anomalous Server Activity / Rare External from Server Compromise / Suspicious File and C2 Compromise / Fast Beaconing to DGA Compromise / Large Number of Suspicious Failed Connections Device / Large Number of Model Alert
Mitre Attack Mapping:
Tactic – Technique – Technique Name
Initial Access - T1189 – Drive-by Compromise Initial Access - T1190 – Exploit Public-Facing Application Initial Access ICS - T0862 – Supply Chain Compromise Initial Access ICS - T0865 – Spearphishing Attachment Initial Access ICS - T0817 - Drive-by Compromise Resource Development - T1588.001 – Malware Lateral Movement ICS - T0843 – Program Download Command and Control - T1105 - Ingress Tool Transfer Command and Control - T1095 – Non-Application Layer Protocol Command and Control - T1571 – Non-Standard Port Command and Control - T1568.002 – Domain Generation Algorithms Command and Control ICS - T0869 – Standard Application Layer Protocol Evasion ICS - T0849 – Masquerading Exfiltration - T1041 – Exfiltration Over C2 Channel Exfiltration - T1567.002 – Exfiltration to Cloud Storage
Customer Case Study: Leading Petrochemical Manufacturer
Headquartered in Saudi Arabia, this industry leading petrochemical manufacturer serves customers in more than 80 countries across diverse markets throughout Europe, Africa, Latin America, the Middle East, China, and Southeast Asia.
Cyber resiliency critical to growth strategy
This leading petrochemical manufacturer’s vision is to be one of the major global players in the production and marketing of designated petrochemicals and downstream products. The company aims to significantly increase its capacity to up to a million metric tons within the next few years.
With cyber-attacks on critical infrastructure increasing 30% globally last year, cyber resiliency is essential to supporting the company’s strategic business goals of:
Maximizing production through efficient asset utilization
Maximizing sales by conducting 90% of its business outside Saudi Arabia
Optimizing resources and processes by integrating with UN Global Compact principles for sustainability and efficiency
Growing its business portfolio by engaging in joint ventures to diversify production and add value to the economy
However, the industry leader faced several challenges in its drive to fortify its cybersecurity defenses.
Visibility gaps delay response time
The company’s existing security setup provided limited visibility to the in-house security team, hindering its ability to detect anomalous network and user activity in real time. This resulted in delayed responses to potential incidents, making proactive issue resolution difficult and any remediation in the event of a successful attack costly and time-consuming.
Manual detection drains resources
Without automated detection and response capabilities, the organization’s security team had to manually monitor for suspicious activity – a time-consuming and inefficient approach that strained resources and left the organization vulnerable. This made it difficult for the team to stay current with training or acquire new skills and certifications, which are core to the ethos of both the company’s owners and the team itself.
Cyber-attacks on critical infrastructure increasing
The petrochemical manufacturer is part of a broader ecosystem of companies, making the protection of its supply chain – both upstream and downstream – critical. With several manufacturing entities and multiple locations, the customer’s internal structure is complex and challenging to secure. As cyber-attacks on critical infrastructure escalate, it needed a more comprehensive approach to safeguard its business and the wider ecosystem.
Keeping and growing skills and focus in-house
To strengthen its cybersecurity strategy, the company considered two options:
Make a significant initial and ongoing investment in a Security Operations Center (SOC), which would involve skills development outside the company and substantial management overhead.
Use a combination of new, automated tools and an outsourced Managed Detection and Response (MDR) service to reduce the burden on internal security specialists and allow the company to invest in upskilling its staff so they can focus on more strategic tasks.
Faced with this choice between entirely outsourcing security and augmenting the security team with new capabilities, the customer chose the second option, selecting Darktrace to automate the company’s monitoring, detection, and response. Today, the petrochemical manufacturer is using:
To alleviate the burden on its lean security team, the company augmented its in-house capabilities with Darktrace’s Managed Detection & Response service. This support acts as an extension of its SOC, providing 24/7 monitoring, investigation, and escalation of high-priority threats. With Darktrace’s global SOC managing alert triage and autonomously containing threats, the organization’s internal team can focus on strategic initiatives. The result is a stronger security posture and increased capacity to proactively address evolving cyber risks – without expanding headcount or sacrificing visibility.
A unique approach to AI
In its search for a new security platform, the company’s Director of Information Technology said Darktrace’s autonomous response capability, coupled with Self-Learning AI-driven threat reduction, were two big reasons for selecting Darktrace over competing products and services.
AI was a huge factor – no one else was doing what Darktrace was doing with [AI].”
Demonstrated visibility
Before Darktrace, the customer had no visibility into the network activity to and from remote worker devices. Some employees need the ability to connect to its networks at any time and from any location, including the Director of Information Technology. The trial deployment of Darktrace / ENDPOINT was a success and gave the team peace of mind that, no matter the location or device, high-value remote workers were protected by Darktrace.
Modular architecture
Darktrace's modular architecture allowed the company to deploy security controls across its complex, multi-entity environment. The company’s different locations run on segregated networks but are still interconnected and need to be protected. Darktrace / NETWORK provides a unified view and coordinated security response across the organization’s entire network infrastructure, including endpoint devices.
Results
The petrochemical manufacturer is using Darktrace across all of its locations and has achieved total visibility across network and user activity. “Darktrace is increasing in value every day,” said the Director of Information Technology.
I don’t have a big team, and Darktrace makes our lives very, very easy, not least the automation of some of the tasks that require constant manual review.”
Time savings frees analysts to focus on proactive security
Darktrace / NETWORK provides continuous, AI-driven monitoring and analysis of the company’s network activity, user behavior, and threat patterns, establishing a baseline of what normal activity looks like, and then alerting analysts to any deviations from normal traffic, activity, and behaviors. Darktrace’s autonomous response capabilities speed up response to detected threats, meaning intervention from the security team is required for fewer incidents and alerts.
In October 2024 alone, Darktrace Cyber AI Analyst saved the team 810 investigation hours, and autonomously responded to 180 anomalous behaviors that were uncovered during the investigations. With Darktrace managing the majority of threat detection and response efforts, the security team has been able to change its day-to-day activity from manual review of traffic and alerts and belated response to activity, to proactively fortifying its detection and response posture and upskilling to meet evolving requirements.
Layered email protection reduces phishing threats
The company’s email infrastructure posed a challenge due to petrochemical industry regulations requiring on-premises email servers, with some security delivered via Microsoft Azure. By integrating Darktrace / EMAIL into the Azure stack, the organization has reduced the volume of phishing emails its users receive by 5%.
“Now we have one more layer of security related to email – every email goes through two filters. If something is not being caught or traced by Azure, it is being detected by Darktrace,” said the Director of Information Technology. “As a result, we’re now seeing only about 15% to 20% of the phishing emails we used to receive before implementing Darktrace.”
Preparing for a secure future
The time saved using Darktrace has helped the security team take proactive steps, including preparing for new cyber resilience regulations for Saudi Arabia’s Critical National Infrastructure, as mandated by the National Cybersecurity Authority (NCA).
“The team now has ample time to prepare policies and procedures that meet the new NCA regulations and, in some cases, enhance the requirements of the new law,” said the Director of Information Technology. “All of this is possible because they don’t need to keep watch; Darktrace takes on so much of that task for them.”
![Darktrace’s detection of the affected device connecting to the suspicious dynamic DNS endpoint, 21ene.ip-ddns[.]com.](https://cdn.prod.website-files.com/626ff4d25aca2edf4325ff97/685c5e35886ec88c0cfe90d1_Screenshot%202025-06-25%20at%201.34.48%E2%80%AFPM.png)
